synapse: rename synapse_public_base_domain to synapse_external_domain

roles/synapse/meta/argument_specs.yaml

@@ -11,7 +11,7 @@ argument_specs:
         description: Matrix server name. This can not be changed without a full reset and database wipe. This will be visible to users.
         type: str
         required: true
-      synapse_public_base_domain:
+      synapse_external_domain:
         description:
           - The public-facing domain that clients use to access synapse, without https://. e.g. matrix.domain.tld
           - This is used to set the public_baseurl option for synapse (with https:// and trailing / added)

roles/synapse/tasks/main.yaml

@@ -39,4 +39,4 @@
       UID: 991
       GID: 991
     service_container_http_port: 8008
-    service_domains: "{{ [synapse_public_base_domain] }}"
+    service_domains: "{{ [synapse_external_domain] }}"

roles/synapse/templates/homeserver.yaml.j2

@@ -7,7 +7,7 @@ media_store_path: /data/media
 log_config: /data/log.yaml
 
 server_name: {{ synapse_server_name }}
-public_baseurl: https://{{ synapse_public_base_domain }}/
+public_baseurl: https://{{ synapse_external_domain }}/
 report_stats: false
 
 listeners: