and add a few assertion on the posted messages content

using momentjs that's already bundled in jiodev.js

https://www.erp5.com/documentation/developer/guideline/module/erp5-Guideline.Module.Creation#set-form-encytype-to-multipart/form-data-when-using-file-upload

as a result, attaching files when submitting support request was not working

Also:
 * post are now HTML and not plain text
 * all event types are returned by
SupportRequest_getCommentPostListAsJson (so that the app can also
display support request used in "traditional" erp5 interface)
 * instead of immediate reindex, we store the "just posted" data in
portal_session.
 * events are created using resource defined as a web site "layout"
property (that's not yet editable)
 * posts do not receive a message-id yet (because ui part is not yet
updated for that), so generate a message-id server side (by just using
id)

* add a `source_reference` field to store message-id
* store the raw content "as is" - there is not preview for this reason (
  because it might be unsafe html or whatever)
* remove proxy roles on scripts. User must have permission.
* minor simplifications

/reviewed-on nexedi/erp5!763

This snapshot were made on Chrome 70 (ChromeOS) with a 1001x932 window
(innerHeight x innerWidth)

To Compare a "screenshot" of a DOM element with a reference snapshot.

This check supports the following parameters:
 *   locator - an element locator
 *   misMatchTolerance - the percentage of mismatch allowed. If this is 0, the
      images must be exactly same. If more than 0, image will also be resized.

https://github.com/niklasvh/html2canvas Copyright (c) 2012 Niklas von Hertzen

from https://github.com/HuddleEng/Resemble.js/blob/v2.10.2/resemble.js © 2013 Huddle

to get stable sort and prevent "random" test failures.

"Restore" sounds a bit strange to me in this context.

So that we can wait for this in the tests

[erp5_officejs] Use upload_dict instead of file_extension to check for correct file-type during notebook upload

Also, exlicitly specify the txt extension during download

/reviewed-on nexedi/erp5!760

/reviewed-on !762

Also, update tests for notebook to check for Upload page

/reviewed-on !764

Fixes rendering when using Chameleon:
  ValueError: only strings can be translated, not: <ERP5Type.Message.Message for ...

/reviewed-on nexedi/erp5!747

/reviewed-on nexedi/erp5!765

adjust font url

This is incubator-echarts-4.1.0-release/dist/echarts.min.js from
https://github.com/apache/incubator-echarts/releases/tag/4.1.0-release

https://www.erp5.com/documentation/developer/guideline/coding/erp5-Guideline.Coding.Best.Practice#use-methods-to-access-properties-in-erp5