Use explicit network aliases, add appservice registration script

servers/mautrix/signal/config.yaml

@@ -191,7 +191,7 @@ appservice:
     # Like the homeserver address, a local non-https address is recommended when the bridge is on the same machine.
     # If the bridge is elsewhere, you must secure the connection yourself (e.g. with https or wireguard)
     # If you want to use https, you need to use a reverse proxy. The bridge does not have TLS support built in.
-    address: http://mautrix-signal:29328
+    address: http://as-mautrix-signal:29328
     # A public address that external services can use to reach this appservice.
     # This is only needed for things like public media. A reverse proxy is generally necessary when using this field.
     # This value doesn't affect the registration file.