Remove messageTypes.inc and replace it by a hook

The list is now maintained in the translatewiki repo:
https://git.wikimedia.org/blob/translatewiki.git/HEAD/groups%2FMediaWiki%2FMediaWiki.yaml

Change-Id: I4a33b22e425cbc1eeaf8b53870ef7b7947e91b40
Merge "Remove messageTypes.inc and replace it by a hook"