RL: Add modules and module styles to page as modules found

This is dependant on
https://gerrit.wikimedia.org/r/#/c/55446/

Changes:
* Deprecates mobileTargets
** Fixes Bug: 47058
* Adds hook EnableMobileModules so other extensions can enable modules
on beta or alpha

Change-Id: I1abd8798189e1a3f6375e473ab944daa82daa1e3
Merge "RL: Add modules and module styles to page as modules found"