Make roles more independent of one another

With this change, the following roles are now only dependent
on the minimal `matrix-base` role:
- `matrix-corporal`
- `matrix-coturn`
- `matrix-mailer`
- `matrix-mxisd`
- `matrix-postgres`
- `matrix-riot-web`
- `matrix-synapse`

The `matrix-nginx-proxy` role still does too much and remains
dependent on the others.

Wiring up the various (now-independent) roles happens
via a glue variables file (`group_vars/matrix-servers`).
It's triggered for all hosts in the `matrix-servers` group.

According to Ansible's rules of priority, we have the following
chain of inclusion/overriding now:
- role defaults (mostly empty or good for independent usage)
- playbook glue variables (`group_vars/matrix-servers`)
- inventory host variables (`inventory/host_vars/matrix.<your-domain>`)

All roles default to enabling their main component
(e.g. `matrix_mxisd_enabled: true`, `matrix_riot_web_enabled: true`).
Reasoning: if a role is included in a playbook (especially separately,
in another playbook), it should "work" by default.

Our playbook disables some of those if they are not generally useful
(e.g. `matrix_corporal_enabled: false`).

roles/matrix-synapse/templates/synapse/homeserver.yaml.j2

@@ -216,10 +216,10 @@ database:
   # The database engine name
   name: "psycopg2"
   args:
-    user: {{ matrix_postgres_connection_username|to_json }}
-    password: {{ matrix_postgres_connection_password|to_json }}
-    database: "{{ matrix_postgres_db_name }}"
-    host: "{{ matrix_postgres_connection_hostname }}"
+    user: {{ matrix_synapse_database_user|to_json }}
+    password: {{ matrix_synapse_database_password|to_json }}
+    database: "{{ matrix_synapse_database_database }}"
+    host: "{{ matrix_synapse_database_host }}"
     cp_min: 5
     cp_max: 10
 
@@ -409,10 +409,10 @@ recaptcha_siteverify_api: "https://www.google.com/recaptcha/api/siteverify"
 ## Turn ##
 
 # The public URIs of the TURN server to give to clients
-turn_uris: ["turn:{{ hostname_matrix }}:3478?transport=udp", "turn:{{ hostname_matrix }}:3478?transport=tcp"]
+turn_uris: {{ matrix_synapse_turn_uris|to_json }}
 
 # The shared secret used to compute passwords for the TURN server
-turn_shared_secret: {{ matrix_coturn_turn_static_auth_secret|to_json }}
+turn_shared_secret: {{ matrix_synapse_turn_shared_secret|to_json }}
 
 # The Username and password if the TURN server needs them and
 # does not use a token
@@ -600,18 +600,18 @@ password_config:
 # If your SMTP server requires authentication, the optional smtp_user &
 # smtp_pass variables should be used
 #
-{% if matrix_mailer_enabled %}
+{% if matrix_synapse_email_enabled %}
 email:
    enable_notifs: true
-   smtp_host: "matrix-mailer"
-   smtp_port: 587
-   require_transport_security: false
-   notif_from: "Matrix <{{ matrix_mailer_sender_address }}>"
+   smtp_host: {{ matrix_synapse_email_smtp_host|to_json }}
+   smtp_port: {{ matrix_synapse_email_smtp_port|to_json }}
+   require_transport_security: {{ matrix_synapse_email_smtp_require_transport_security|to_json }}
+   notif_from: {{ matrix_synapse_email_notif_from|to_json }}
    app_name: Matrix
    notif_template_html: notif_mail.html
    notif_template_text: notif_mail.txt
    notif_for_new_users: True
-   riot_base_url: "https://{{ hostname_riot }}"
+   riot_base_url: {{ matrix_synapse_email_riot_base_url|to_json }}
 {% endif %}
 
 

roles/matrix-synapse/templates/synapse/systemd/matrix-synapse.service.j2

@@ -1,19 +1,12 @@
 [Unit]
 Description=Matrix Synapse server
-After=docker.service
-Requires=docker.service
-{% if not matrix_postgres_use_external %}
-Requires=matrix-postgres.service
-After=matrix-postgres.service
-{% endif %}
-{% if matrix_s3_media_store_enabled %}
-After=matrix-goofys.service
-Requires=matrix-goofys.service
-{% endif %}
-{% if matrix_mailer_enabled %}
-Wants=matrix-mailer.service
-{% endif %}
-Wants=matrix-coturn.service
+{% for service in matrix_synapse_systemd_required_services_list %}
+Requires={{ service }}
+After={{ service }}
+{% endfor %}
+{% for service in matrix_synapse_systemd_wanted_services_list %}
+Wants={{ service }}
+{% endfor %}
 
 [Service]
 Type=simple