synapse: support server notices

So that init script doesn’t complain.

roles/alpine/tasks/main.yml

@@ -19,6 +19,13 @@
     mode: 0644
   notify: restart networking
 
+- name: Create network interface directory
+  file:
+    path: /etc/network/interfaces.d
+    state: directory
+    mode: "0755"
+  notify: restart networking
+
 - name: Set up network interfaces
   template:
     dest: /etc/network/interfaces

roles/synapse/templates/homeserver.yaml.j2

@@ -28,6 +28,11 @@ allow_public_rooms_over_federation: true
 presence:
   enabled: false
 
+server_notices:
+   system_mxid_localpart: server
+   system_mxid_display_name: "Server notices"
+   room_name: "Server notices"
+
 #trusted_key_servers:
 #  - server_name: "matrix.org"