* Split tidy implementations into a class hierarchy
* Bring all tidy configuration into a single associative array and
deprecate the old configuration.
* Remove $wgAlwaysUseTidy
This is preparatory to replacement of Tidy (T89331). I used the name
"Raggett" for things relating to Dave Raggett's Tidy, since if we use
"tidy" to mean the new abstract system as well as Raggett's tidy, it
gets confusing.
Change-Id: I77af1a16cbbb47fc226d05fb9aad56c58e8910b5
