Add RL targets support to OutputPage

The target URI parameter is already used by ResourceLoaderStartUpModule
to filter modules, this change introduces the ability to produce
mobile-aware load.php links in the core and filter out modules not suitable
for current target.

Change-Id: Ie03990e11d9a0ac8cd81dd0aae5c5a95f1d23e81
Merge "Add RL targets support to OutputPage"