Use upstream Docker image for amd64 rather than self-build

roles/custom/matrix-client-hydrogen/templates/config.json.j2

@@ -3,7 +3,7 @@
 	"defaultHomeServer": {{ matrix_client_hydrogen_default_hs_url | string | to_json }},
 	"bugReportEndpointUrl": {{ matrix_client_hydrogen_bugReportEndpointUrl | to_json }},
 	"themeManifests": [
-		"assets/theme-Element.json"
+		"assets/theme-element.json"
 	],
 	"defaultTheme": {
 		"light": "element-light",

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

@@ -24,6 +24,7 @@ ExecStart={{ devture_systemd_docker_base_host_command_docker }} run --rm --name
 			{% 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 \
+			--mount type=bind,src={{ matrix_client_hydrogen_data_path }}/config.json,dst=/usr/share/nginx/html/config.json,ro \
 			{% for arg in matrix_client_hydrogen_container_extra_arguments %}
 			{{ arg }} \
 			{% endfor %}