Various /relationship-editor endpoint fixes

Fixes detection/error messages for unrecognized parameters, and
validates link type ids with the given entity types.
Merge remote-tracking branch 'bitmap/re-endpoint-fixes'

* bitmap/re-endpoint-fixes:
  Various /relationship-editor endpoint fixes
Merge branch 'kill-admin-config-sh'

* kill-admin-config-sh:
  Kill off admin/config.sh, moving it instead into DBDefs like everything else.
Merge branch 'master' into beta

* master:
  Various /relationship-editor endpoint fixes

Conflicts:
	lib/MusicBrainz/Server/Controller/RelationshipEditor.pm
	t/lib/t/MusicBrainz/Server/Controller/RelationshipEditor.pm