Deprecated wfMsg, wfMsgForContent, wfMsgExt

using wfMessage like described on
https://www.mediawiki.org/wiki/Manual:Messages_API
Changed some method calls because there was no need for transformation or
parse
Some keys need to be lowercase

Change-Id: I8db8f7ed7fbbd7dca4963ad1b58851c61b847d61
Merge "Deprecated wfMsg, wfMsgForContent, wfMsgExt"