Move roles/matrix* to roles/custom/matrix*

This paves the way for installing other roles into `roles/galaxy` using `ansible-galaxy`,
similar to how it's done in:

- https://github.com/spantaleev/gitea-docker-ansible-deploy
- https://github.com/spantaleev/nextcloud-docker-ansible-deploy

In the near future, we'll be removing a lot of the shared role code from here
and using upstream roles for it. Some of the core `matrix-*` roles have
already been extracted out into other reusable roles:

- https://github.com/devture/com.devture.ansible.role.postgres
- https://github.com/devture/com.devture.ansible.role.systemd_docker_base
- https://github.com/devture/com.devture.ansible.role.timesync
- https://github.com/devture/com.devture.ansible.role.vars_preserver
- https://github.com/devture/com.devture.ansible.role.playbook_runtime_messages
- https://github.com/devture/com.devture.ansible.role.playbook_help

We just need to migrate to those.

roles/custom/matrix-grafana/templates/dashboards.yaml.j2

@@ -0,0 +1,9 @@
+apiVersion: 1
+
+providers:
+  - name: {{ matrix_server_fqn_matrix }} - Dashboards
+    folder: '' # The folder where to place the dashboards
+    type: file
+    allowUiUpdates: true
+    options:
+      path: /etc/grafana/dashboards

roles/custom/matrix-grafana/templates/datasources.yaml.j2

@@ -0,0 +1,8 @@
+apiVersion: 1
+
+datasources:
+  - name: {{ matrix_server_fqn_matrix }} - Prometheus
+    type: prometheus
+    # Access mode - proxy (server in the UI) or direct (browser in the UI).
+    access: proxy
+    url: http://matrix-prometheus:9090

roles/custom/matrix-grafana/templates/grafana.ini.j2

@@ -0,0 +1,29 @@
+[server]
+root_url = "https://{{ matrix_server_fqn_grafana }}"
+
+[security]
+# default admin user, created on startup
+admin_user = "{{ matrix_grafana_default_admin_user }}"
+
+# default admin password, can be changed before first start of grafana, or in profile settings
+admin_password = """{{ matrix_grafana_default_admin_password }}"""
+
+# specify content_security_policy to add the Content-Security-Policy header to your requests
+content_security_policy = "{{ matrix_grafana_content_security_policy }}"
+
+# specify content security policy template to customized template
+{% if matrix_grafana_content_security_policy_customized %}
+content_security_policy_template = """{{ matrix_grafana_content_security_policy_template }}"""
+{% endif %}
+
+allow_embedding = {{ matrix_grafana_allow_embedding }}
+
+[auth.anonymous]
+# enable anonymous access
+enabled = {{ matrix_grafana_anonymous_access }}
+
+# specify organization name that should be used for unauthenticated users
+org_name = "{{ matrix_grafana_anonymous_access_org_name }}"
+
+[dashboards]
+default_home_dashboard_path = {{ matrix_grafana_default_home_dashboard_path }}

roles/custom/matrix-grafana/templates/systemd/matrix-grafana.service.j2

@@ -0,0 +1,43 @@
+#jinja2: lstrip_blocks: "True"
+[Unit]
+Description=matrix-grafana
+{% for service in matrix_grafana_systemd_required_services_list %}
+Requires={{ service }}
+After={{ service }}
+{% endfor %}
+{% for service in matrix_grafana_systemd_wanted_services_list %}
+Wants={{ service }}
+{% endfor %}
+DefaultDependencies=no
+
+[Service]
+Type=simple
+Environment="HOME={{ matrix_systemd_unit_home_path }}"
+ExecStartPre=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} kill matrix-grafana 2>/dev/null || true'
+ExecStartPre=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} rm matrix-grafana 2>/dev/null || true'
+
+
+ExecStart={{ matrix_host_command_docker }} run --rm --name matrix-grafana \
+			--log-driver=none \
+			--user={{ matrix_user_uid }}:{{ matrix_user_gid }} \
+			--cap-drop=ALL \
+			--read-only \
+			--network={{ matrix_docker_network }} \
+			{% if matrix_grafana_container_http_host_bind_port %}
+			-p {{ matrix_grafana_container_http_host_bind_port }}:3000 \
+			{% endif %}
+			-v {{ matrix_grafana_config_path }}:/etc/grafana:z \
+			-v {{ matrix_grafana_data_path }}:/var/lib/grafana:z \
+			{% for arg in matrix_grafana_container_extra_arguments %}
+			{{ arg }} \
+			{% endfor %}
+			{{ matrix_grafana_docker_image }}
+
+ExecStop=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} kill matrix-grafana 2>/dev/null || true'
+ExecStop=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} rm matrix-grafana 2>/dev/null || true'
+Restart=always
+RestartSec=30
+SyslogIdentifier=matrix-grafana
+
+[Install]
+WantedBy=multi-user.target