Closes T984

Closes T981

This new release fixes multi-line strings and comments highlighting bugs
(see https://github.com/wcoder/highlightjs-line-numbers.js/pull/22 and
https://github.com/wcoder/highlightjs-line-numbers.js/pull/30).

  - prefer to request file changes list asynchronously as it can take some time
    to compute for revision with numerous modifications

  - dynamically insert diff panels into the DOM

  - set the maximum number of displayed diffs to 1000

This commit adds the list of changed files in the revision
view but also the diffs (unified and side-by-side) of each
changed file.

Those new features are reachable from the "Changes" tab
in the revision view. Computation of file diffs will
be requested on the fly as the view is scrolled.

Regarding the diffs, they are only computed for textual
contents and diffs larger than 20 kB will not be computed
by default (the user can still manually request it
if needed).

Closes T921

Closes T972

Closes T971

  - persist cooking tasks list across browser sessions
  - enable to remove entirely or partially tasks from that list
  - ensure tasks list synchronization on browser tab focus
  - hide modals when replies of vault requests are received
  - fix progress bar color when a task failed

Closes T963

Closes: T949

Related: T949

Closes: T952

Related: T952

Closes T951