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/localectl

@@ -22,4 +22,6 @@ profile localectl @{exec_path} {
   /usr/share/kbd/keymaps/{,**} r,
 
   include if exists <local/localectl>
-}
+}
+
+# vim:syntax=apparmor