Send cache purges for action=raw after editing user css/js

Send cache purges for action=raw after editing user css/js

These types of requests can be cached for a short time (~5 min) in
Squid/Varnish.

Change importScript to be consistent with importStylesheet in the query
parameter order (title, action, ctype).

We only send purges for the exact urls as used by importScript and
importStylesheet.

Note: ResourceLoader things have their cache handled separately and
aren't affected by this change.

Users like instant updating of scripts after having changed them.

Bug: 56874
Change-Id: Idaa8552cf371dbafeb8b730f35b3b5c4fc339fb0