synapse: Add support for appservices and use secrets better

roles/synapse/templates/appservice-registration.yaml.j2

@@ -0,0 +1,21 @@
+---
+# vim:ft=yaml
+# {{ ansible_managed }}
+{% set id = item.destination.split('/')[-1].split('-')[0] %}
+{% set appservice = synapse_appservices | selectattr('id', 'equalto', id) | first %}
+
+id: {{ id }}
+url: http://{{ appservice.host }}:8080
+as_token: {{ appservice.as_token }}
+hs_token: {{ appservice.hs_token }}
+sender_localpart: {{ id }}senderlocalpart
+rate_limited: false
+namespaces:
+    users:
+        - regex: ^@{{ id }}bot:{{ synapse_server_name | replace('.', '\.') }}$
+          exclusive: true
+        - regex: ^@{{ id }}_.*:{{ synapse_server_name | replace('.', '\.') }}$
+          exclusive: true
+de.sorunome.msc2409.push_ephemeral: true
+receive_ephemeral: true
+io.element.msc4190: true