erp5_document_scanner: add an alarm which will delete outdated (>5 days old) active_process created by the dialog.

With this, we can search easily active processes used by document scanner and remove them

With the size close to the thumbnail, to replace the `new` button text

Drop the current displayed text

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