Consistent usage of matrix username and groupname, not uid and gid

This should be a no-op, no migration necessary.

roles/matrix-synapse/tasks/goofys/setup_install.yml

@@ -17,8 +17,8 @@
     path: "{{ matrix_synapse_media_store_path }}"
     state: directory
     mode: 0750
-    owner: "{{ matrix_user_uid }}"
+    owner: "{{ matrix_user_username }}"
-    group: "{{ matrix_user_gid }}"
+    group: "{{ matrix_user_username }}"
   when: "not local_path_matrix_synapse_media_store_path_stat.failed and not local_path_matrix_synapse_media_store_path_stat.stat.exists"
 
 - name: Ensure goofys environment variables file created