Part of MDL-75966
This commit adds a cache-busting loader API for use in the TinyMCE
plugin.
This is not for use in any TinyMCE subplugins at this time as we have no
use-case outside of AMD modules.
This loader ensures that only files within the js/tiny directory are
loaded, and it only supports either .js or .css files at this time.
The client-side of the loader makes use of the jsrevision as a
cache-buster, including for CSS files included with TinyMCE.
If the revision is negative, then files are not cached.
If the revision is positive, then the requested file is cached in a
candidate file and served using aggressive cache headers.
David Woloszyn