Drop the current displayed text

We will handle contrast differently

To translate all texts, we added more promises and queues to make sure everything works as expected

Clean up and Change all gadget's CSS rules to be prefixed by  `div[data-gadget-url$="gadget_document_scanner.html"]`

The http response should return a 200 response in case of success. The response body may contain a local reference of the uploaded image

Request body should contain the image data and the active process relative url (depending on which erp5 context the script is called)

make jslint happy

* change the `extra renderjs` parameters list to pass a Python script to call when a new image is cropped.
* change the gadget to use jio.util.ajax with the script full url (provided by the server)

Change the gadget checkValidity method to return false when:
- no thumbnail has been generated
- a thumbnail upload is in failed state

The default value is a JSON containing 2 keys:
- the relative_url of an active process
- the list of active process image content to aggregate
By default, when the field is rendered for the first time, this tales expression is evaluated and a new active process is created at that point.
So, default json is like: {active_process: 'portal_activities/1234', image_list: []}
* store the active_process relative_url in the gadget state in the render method
* store the image_list in the gadget state in the render_method
* change getContent method to send a json build from the active_process and image_list state

If device_id is propagated to onStateChange, it means we have a new value. Then, check if we have this property is enough to switch

XXX
Allow to show previously uploaded image.
Allow to delete or retry uploading.

Form submittion only send the active process informations.

Stop relying of CSS hide/show attributes.
Instead, only put needed elements in the DOM.

Like a real-world user.

__ac_name & __ac_password are only useful to get a cookie, so only use them
when the test is actually expecting a cookie.

One inline javascript snippet less.

ZODB Components: Preparation of erp5_base migration from FS: Fix pylint no-name-in-module on newTempXXX (04b49859).

Change upgrader internal API to use `filter_dict` instead of `filter`
which is a builtin.
Remove a lot of unused code in extensions

/reviewed-on !1014

ZODB Components: Preparation of erp5_base migration from FS: Fix pylint no-name-in-module on newTempXXX (04b49859).