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-client-hydrogen/templates/config.json.j2

@@ -0,0 +1,12 @@
+{
+	"push": {{ matrix_client_hydrogen_push | to_json }},
+	"defaultHomeServer": {{ matrix_client_hydrogen_default_hs_url | string | to_json }},
+	"bugReportEndpointUrl": {{ matrix_client_hydrogen_bugReportEndpointUrl | to_json }},
+	"themeManifests": [
+		"assets/theme-Element.json"
+	],
+	"defaultTheme": {
+		"light": "element-light",
+		"dark": "element-dark"
+	}
+}

roles/custom/matrix-client-hydrogen/templates/nginx.conf.j2

@@ -0,0 +1,66 @@
+#jinja2: lstrip_blocks: "True"
+# This is a custom nginx configuration file that we use in the container (instead of the default one),
+# because it allows us to run nginx with a non-root user.
+#
+# For this to work, the default vhost file (`/etc/nginx/conf.d/default.conf`) also needs to be removed.
+# (mounting `/dev/null` over `/etc/nginx/conf.d/default.conf` works well)
+#
+# The following changes have been done compared to a default nginx configuration file:
+# - default server port is changed (80 -> 8080), so that a non-root user can bind it
+# - various temp paths are changed to `/tmp`, so that a non-root user can write to them
+# - the `user` directive was removed, as we don't want nginx to switch users
+
+worker_processes 1;
+
+error_log /var/log/nginx/error.log warn;
+pid /tmp/nginx.pid;
+
+
+events {
+	worker_connections 1024;
+}
+
+
+http {
+	proxy_temp_path /tmp/proxy_temp;
+	client_body_temp_path /tmp/client_temp;
+	fastcgi_temp_path /tmp/fastcgi_temp;
+	uwsgi_temp_path /tmp/uwsgi_temp;
+	scgi_temp_path /tmp/scgi_temp;
+
+	include /etc/nginx/mime.types;
+	default_type application/octet-stream;
+
+	log_format main '$remote_addr - $remote_user [$time_local] "$request" '
+					'$status $body_bytes_sent "$http_referer" '
+					'"$http_user_agent" "$http_x_forwarded_for"';
+
+	access_log /var/log/nginx/access.log main;
+
+	sendfile on;
+	#tcp_nopush on;
+
+	keepalive_timeout 65;
+
+	#gzip on;
+
+	server {
+		listen 8080;
+		server_name localhost;
+
+		root /usr/share/nginx/html;
+
+		location / {
+			index index.html index.htm;
+		}
+
+		location ~* ^/(config(.+)?\.json$|(.+)\.html$|i18n) {
+			expires -1;
+		}
+
+		error_page 500 502 503 504 /50x.html;
+		location = /50x.html {
+			root /usr/share/nginx/html;
+		}
+	}
+}

roles/custom/matrix-client-hydrogen/templates/systemd/matrix-client-hydrogen.service.j2

@@ -0,0 +1,39 @@
+#jinja2: lstrip_blocks: "True"
+[Unit]
+Description=Matrix Hydrogen Client
+{% for service in matrix_client_hydrogen_systemd_required_services_list %}
+Requires={{ service }}
+After={{ 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-client-hydrogen 2>/dev/null || true'
+ExecStartPre=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} rm matrix-client-hydrogen 2>/dev/null || true'
+
+ExecStart={{ matrix_host_command_docker }} run --rm --name matrix-client-hydrogen \
+			--log-driver=none \
+			--user={{ matrix_user_uid }}:{{ matrix_user_gid }} \
+			--cap-drop=ALL \
+			--read-only \
+			--network={{ matrix_docker_network }} \
+			{% if matrix_client_hydrogen_container_http_host_bind_port %}
+			-p {{ matrix_client_hydrogen_container_http_host_bind_port }}:8080 \
+			{% endif %}
+			--tmpfs=/tmp:rw,noexec,nosuid,size=10m \
+			--mount type=bind,src={{ matrix_client_hydrogen_data_path }}/nginx.conf,dst=/etc/nginx/nginx.conf,ro \
+			{% for arg in matrix_client_hydrogen_container_extra_arguments %}
+			{{ arg }} \
+			{% endfor %}
+			{{ matrix_client_hydrogen_docker_image }}
+
+ExecStop=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} kill matrix-client-hydrogen 2>/dev/null || true'
+ExecStop=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} rm matrix-client-hydrogen 2>/dev/null || true'
+Restart=always
+RestartSec=30
+SyslogIdentifier=matrix-client-hydrogen
+
+[Install]
+WantedBy=multi-user.target