even if the `_converse.bosh_session` instance does not exist.

We do this to avoid trying to reconnect with stale tokens upon
reconnection. Especially relevant for anonymous connections, but could
also be applicable when switching between websocket and BOSH connections
when reconnecting.

Also renamed `startNewBOSHSession` to `startNewPreboundBOSHSession`

I.e. also when we're reconnecting.

Otherwise the `_converse.bosh_session` object doesn't get recreated and
we don't cache the BOSH tokens.

above logging in with passed in JID and password, since the password
might be an expired token.

otherwise values get tacked on, causing problems when reconnecting.

Because when we reconnect anonymously, we get a new JID, so it's as if
it's a completely new user.

So that the BOSH connection will be restored before we trigger `connectionInitialized`

It's unlikely that `keepalive` needs to be set to `false`, but there are
some edge cases where it might be useful.

Here's a breakdown of the different configurations of `keepalive` and `auto_join`:

---

* auto_login: false, keepalive: true

This is the default config. Users need to log in manually, but then
Converse will try to reconnect them when the page reloads.

* auto_login: true, keepalive: true

Also very popular configuration. Used with `credentials_url` or `prebind_url`.

* auto_login = `true`, keepalive = `false`

Not sure what this could be useful for. No currently known application.

* auto_login = `false`, keepalive = `false`

Useful when you want some kind of specific action to trigger login, but
you don't want to maintain that state across page reloads.

Also relevant when using a websocket connection with anonymous login.
With websocket it's impossible to maintain anonymous sessions across page
reload because the the session gets removed server-side as soon as the
websocket connection drops and the server won't accept a full JID with
password for an anonymous connection anyway (which could happen upon
page reload when Converse tries to login in again if `keepalive` was `true`).

triggering connectionInitialized.

That way, when listening for `connectionInitialized`, we'll know when it
fires whether we've attached to a BOSH connection or not.

* Translated using Weblate (Norwegian Bokmål)

Currently translated at 70.9% (268 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/nb_NO/

* Translated using Weblate (Hebrew)

Currently translated at 100.0% (378 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/he/

* Translated using Weblate (German)

Currently translated at 100.0% (378 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/de/

* Translated using Weblate (French)

Currently translated at 100.0% (378 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/fr/

* Translated using Weblate (Spanish)

Currently translated at 100.0% (378 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/es/

* Translated using Weblate (Japanese)

Currently translated at 98.1% (371 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/ja/

* Translated using Weblate (Galician)

Currently translated at 100.0% (378 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/gl/

* Translated using Weblate (Lithuanian)

Currently translated at 80.4% (304 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/lt/

* Added translation using Weblate (Portuguese)

* Translated using Weblate (Arabic)

Currently translated at 81.7% (309 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/ar/

* Translated using Weblate (Czech)

Currently translated at 100.0% (378 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/cs/

* Translated using Weblate (Chinese (Simplified))

Currently translated at 38.4% (145 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/zh_Hans/

* Translated using Weblate (Turkish)

Currently translated at 4.8% (18 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/tr/

* Translated using Weblate (Portuguese)

Currently translated at 83.1% (314 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/pt/

* Translated using Weblate (Portuguese)

Currently translated at 82.5% (312 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/pt/

* Translated using Weblate (Romanian)

Currently translated at 34.4% (130 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/ro/

* Translated using Weblate (Romanian)

Currently translated at 38.4% (145 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/ro/

* Translated using Weblate (Romanian)

Currently translated at 54.0% (204 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/ro/

* Translated using Weblate (Arabic)

Currently translated at 86.5% (327 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/ar/

* Translated using Weblate (Romanian)

Currently translated at 54.8% (207 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/ro/

* Translated using Weblate (Portuguese (Brazil))

Currently translated at 63.2% (239 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/pt_BR/

* Translated using Weblate (Portuguese)

Currently translated at 82.8% (313 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/pt/

* Translated using Weblate (Basque)

Currently translated at 94.2% (356 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/eu/

* Translated using Weblate (Galician)

Currently translated at 100.0% (378 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/gl/

* Translated using Weblate (Turkish)

Currently translated at 16.9% (64 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/tr/

* Translated using Weblate (Chinese (Simplified))

Currently translated at 40.5% (153 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/zh_Hans/

* Translated using Weblate (Polish)

Currently translated at 80.7% (305 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/pl/

* Translated using Weblate (Chinese (Simplified))

Currently translated at 40.2% (152 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/zh_Hans/

* Translated using Weblate (Portuguese (Brazil))

Currently translated at 77.5% (293 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/pt_BR/

* Translated using Weblate (Portuguese)

Currently translated at 88.9% (336 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/pt/

* Translated using Weblate (Russian)

Currently translated at 96.8% (366 of 378 strings)

Translation: Converse.js/Translations
Translate-URL: https://hosted.weblate.org/projects/conversejs/translations/ru/

* Fix: async SetUserJID

If `auto_login` is false, we shouldn't log in, so we only try to log in when
it is true. Otherwise we still try to restore the BOSH session (if applicable).

rename `autoJoin` to `connect`

- Split between `login` auth and the rest (`external`, `anonymous`, `prebind`)
- It doesn't make sense to pass along credentials when not using `login` auth so avoid that flow.
- It's not necessary to pass the `reconnecting` flag to `attemptNonPreboundSession`

given that it's implicit and can cause confusion

* Don't set JID resource when logging in anonymously. The resource will be set by the server.
* Don't wipe the `id` from the session when clearing it.

So that we can remove the textarea if we're a visitor in a moderated room.

Instead optimize in other ways.

Also:
- Don't fade in when `animate` is false.
- `trimChats` now gets called in `afterShown`.
- Add now event `beforeShowingChatView`

and bump default timeout

Also let `_converse.api.waitUntil` use it if a function is passed in.

These two commit should ideally be one, but I inadvertently pushed to
remote too early.