Pass media_url and displayname to Heisenbridge - do not make it guess

Without explicitly passing the `media_url` configuration,
Heisenbridge would try to guess it. It works most of the time,
but some people are experiencing trouble with it.

There's no need for wasteful work and for potential unreliability,
so we now configure the `media_url` explicitly.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2932

roles/custom/matrix-bridge-heisenbridge/defaults/main.yml

@@ -30,7 +30,15 @@ matrix_heisenbridge_homeserver_url: "{{ matrix_homeserver_container_url }}"
 matrix_heisenbridge_appservice_token: ''
 matrix_heisenbridge_homeserver_token: ''
 
-# Default registration file
+matrix_heisenbridge_config_media_url: "{{ matrix_homeserver_url }}"
+matrix_heisenbridge_config_displayname: "Heisenbridge"
+
+matrix_heisenbridge_registration_yaml_heisenbridge:
+  media_url: "{{ matrix_heisenbridge_config_media_url }}"
+  displayname: "{{ matrix_heisenbridge_config_displayname }}"
+
+# Default registration file consumed by both the homeserver and Heisenbridge.
+# Besides registration information, it contains configuration (see the heisenbridge key).
 matrix_heisenbridge_registration_yaml:
   id: heisenbridge
   url: http://matrix-heisenbridge:9898
@@ -44,5 +52,6 @@ matrix_heisenbridge_registration_yaml:
         exclusive: true
     aliases: []
     rooms: []
+  heisenbridge: "{{ matrix_heisenbridge_registration_yaml_heisenbridge }}"
 
 matrix_heisenbridge_registration: "{{ matrix_heisenbridge_registration_yaml | from_yaml }}"