Remove various redundant '@license' tags in file headers

Redundant given this is the project-wide license already,
especially in file headers that already include the GPL license
header.

This and other minor fixups based on feedback from Ie0cea0ef5027c7e5.

* Add @file where missing.
* Move @ingroup and @deprecated from file to class doc where needed.

Change-Id: I7067abb7abee1f0c238cb2536e16192e946d8daa