When restoring an already entered room from cache.
Otherwise we end up with an empty history.

Otherwise we end up with no textarea when rendering a MUC that starts
with connection_status of entered but which then needs to reconnnect.

if we're just going to clear them again

This avoids flashing of messages followed by a spinner.

Currently translated at 88.2% (374 of 424 strings)

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

Currently translated at 93.4% (396 of 424 strings)

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

Currently translated at 100.0% (424 of 424 strings)

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

Currently translated at 35.4% (150 of 424 strings)

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

Currently translated at 100.0% (424 of 424 strings)

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

Currently translated at 100.0% (424 of 424 strings)

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

Currently translated at 70.8% (300 of 424 strings)

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

Currently translated at 100.0% (424 of 424 strings)

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

Currently translated at 82.5% (350 of 424 strings)

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

Currently translated at 72.2% (306 of 424 strings)

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

Currently translated at 76.7% (325 of 424 strings)

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

Currently translated at 100.0% (424 of 424 strings)

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

Currently translated at 100.0% (424 of 424 strings)

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

Currently translated at 100.0% (424 of 424 strings)

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

- Add config variable `muc_show_logs_before_join`
- Restore nickname form for the original use-case (when not showing MAM logs before joining).
- Render nickname form in the `.muc-bottom-panel` when showing MAM logs (instead of in a modal)
- Show a message when there aren't any archived messages to show
- Fix converse-mam so that chat logs are properly fetched before entering a MUC

closes #1266

`streamFeaturesAdded` should only be triggered once we've received them
from the server.

This appears to be a timing bug, likely introduced by the IndexedDB
refactoring.

- Retracted moderated message are not editable
- Use "removed" for user-facing text

not while tearing down, otherwise the modals get removed while
reconnecting and we have stale references to modals no longer in the
DOM.