Long (sigh) explanation in T203587#4569698. Also, simplified the way
TagMultiselect are generated, this one and the one for change tags.
This new selector is back-compat both with the old textarea and the OOUI
checkboxMultiselect; actually, this one is //fully// compatible with the
old textarea.
Add validation for throttle parameters and unit tests for validation
(split from I976c95658cddb2585910b6f8a5f047aadc4e4d47).
Added a trim when retrieving throttle identifier to allow syntax like
'ip, user'.
Improved the message shown on history.
Re-added the maintenance script to clean DB.
As I wrote in the task, a review by two other people would be great, at
least for the maintenance script (it could potentially break the DB).
Bug: T203587
Bug: T203336
Bug: T203584
Bug: T203585
Depends-On: I3b2e763bd8835207dc5df1db43d3e1881e6961c3
Change-Id: I7831dbb0bab55807392ac1f7915d6cb0cb713593
