feat(groups/{c,d,f,s}*): vim syntax support

Add vim modeline instructing the editor to use syntax plugin provided by apparmor.
Continuation of #392 to keep the diff list relatively short.

apparmor.d/groups/systemd/systemd-oomd

@@ -40,3 +40,5 @@ profile systemd-oomd @{exec_path} flags=(attach_disconnected) {
 
   include if exists <local/systemd-oomd>
 }
+
+# vim:syntax=apparmor