Move theme namespace registration to themes package, simplify view resolution
Fixes #6 (page type view switching)
Updates all relveant classes to work with new Monal APIs and to work
with the latest changes to the Data package.
Merge branch 'master' of https://github.com/juice49/Monal-Pages into juice49-master

Conflicts:
	src/controllers/FrontendPageController.php
Merge branch 'juice49-master'