resourceloader: Add support for delivering templates

A base ResourceLoaderModule::getTemplates() exists for subclasses
to override. An implementation is provided for ResourceLoaderFileModule.

For file modules, templates can be specified in the following manner:

'example' => array(
	'templates' => array(
		'bar' => 'templates/foo.html',
	),
	'scripts' => 'example.js',
),

The delivery system is template language agnostic, and currently
only supports "compiling" plain HTML templates.

This also adds template support to the following modules as a POC:
* mediawiki.feedback
* mediawiki.action.view.postEdit
* mediawiki.special.upload

Works with $wgResourceLoaderStorageEnabled

Change-Id: Ia0c5c8ec960aa6dff12c9626cee41ae9a3286b76
Merge "resourceloader: Add support for delivering templates"