Replace homedir permission with only config path

This makes the application perfectly usable (including being able to
save and load its own config), but without giving it access to the whole
home directory.

And yes, the config directory it's expecting is really
~/.config/.X-AIR-Edit, with that exact capitalization, and with the
leading dot.

com.behringer.XAirEdit.yml

@@ -10,7 +10,7 @@ finish-args:
 - --socket=x11
 - --share=network
 - --device=dri
-- --filesystem=home
+- --persist=.config/.X-AIR-Edit
 modules:
 - name: patchelf
   sources: