PLATFORM-292: WikiaNewtalk - improve memcache key structure
SharedHelp: use wfSharedMemcKey()
Revert "Add URL to Wikia Extensions and $wgExtensionCredits to some that were missing it"
Merge pull request #5839 from Wikia/revert-5745-dev

Revert "Add URL to Wikia Extensions and $wgExtensionCredits to some that...
Merge pull request #5814 from Wikia/wikia_newtalk_memcache_key_layout

PLATFORM-292: WikiaNewtalk - improve memcache key structure
Merge pull request #5816 from Wikia/shared-help-use-wfSharedMemcKey

PLATFORM-292 - SharedHelp: use wfSharedMemcKey()