Allow for global renaming of users

* Adds Special:GlobalRenameUser for trusted users to rename
  global accounts
* Assumes that the user performing the rename has the ability
  to move whatever pages are necessary on the local wikis,
  including suppressing redirects
* Uses a new database table to store status and hopefully
  avoid race conditions
* Added hooks to prevent users from logging in or creating
  a new account if a rename to or from that username is
  in progress
* If a user is currently being renamed and tries accessing the
  wiki, their session is cleared.
* Adds Special:GlobalRenameProgress for users to check on the
  status of a rename, and which wikis are still pending.

Bug: 14862
Change-Id: Id78577e95d73fbcdcb72e80ef25a34106ac91aa2
Refactor global renaming

Divide the big SpecialGlobalRenameUser which did everything
into one class per task. That way we get tiny classes with
low complexity which can also be unit tested easily.

Change-Id: I277d785f887af5b24809110c0182de77b7d26eec
Add extension credits for global rename

Change-Id: I8fc3a1efab9ff901eccbfde8b3daac433ac473c0
Localisation updates from https://translatewiki.net.

Change-Id: I470eb767a185929c027b6d3eab7d6c678d31b8c7
Don't use $wgUser in SpecialMergeAccount

Change-Id: I6afbe3dc61c56daf9a637cb69ab71f765dd90081
Message improvements

* Correct spelling in one message.
* Make GENDER usage clearer.

Change-Id: Id2e318c224dd29bff7e17fed1a95c9e7dd4d3f9a
Merge "Don't use $wgUser in SpecialMergeAccount"
Ask for confirmation before renaming a user globally

Change-Id: I534cc79830ec1bc29d3a474ff1d203b3b6342bee
Localisation updates from https://translatewiki.net.

Change-Id: I166d1aa5c53a719ce7918f9321fc224cc1f2e876
Merge "Ask for confirmation before renaming a user globally"
Remove renaming.txt - Outdated and misleading

Change-Id: Iff2d4d308d8c60efc6710bc01b549b1a3d88f547
Localisation updates from https://translatewiki.net.

Change-Id: I3c04df61bb3cdd0886cabc04563b8350aad9a961
Add --attachbroken option to migrateAccount.php

Bug: 61876
Change-Id: I6882c14e300869938af750ef774bb8ff6c243605
Merge "Add --attachbroken option to migrateAccount.php"
Show a link to Special:GlobalRenameProgress if a global rename is in progress

Change-Id: I01217b81fa3e3415c4cb240ff35bf824a98cf632
Merge "Show a link to Special:GlobalRenameProgress if a global rename is in progress"
Localisation updates from https://translatewiki.net.

Change-Id: I98a93a94caa8577cdcc80891037b6b5c6876ffde
Fix division by zero in Special:WikiSets

Bug: 58475
Change-Id: If141c70328812bb578de863c7be7e637239a7da0
Only show relevant log entries on MultiLock

Bug: 57253
Change-Id: Ia820733384071cd8360a48b8cd210a0086ee0ca0
Clarify migrateAccount.php options

Yes, it's a bit verbose but better than being misleading.

Change-Id: I59639c519c26c48bc1c5bfda43f78120d70af682