nuke feldgrau

Posted under Tags

BUR #14650 has been approved by @nonamethanks.

nuke feldgrau
deprecate feldgrau

We already have tags for german uniforms, we specifically don't tag colors without applying them to something (see the wikis for blue or red) at all, and the tag isn't applied with any real consistency (post #5998224 and post #5864951 are completely different shades of green, and post #5939249 isn't even visibly green at all).