synapse workers/nginx: handle media_repository worker endpoints on federation port

to prevent "404 on the federation port for the path `/_matrix/media`,
if a remote server is trying to get the media object on federation
port, see https://github.com/matrix-org/synapse/issues/8695 "

https://github.com/matrix-org/synapse/pull/8701

roles/matrix-nginx-proxy/templates/nginx/conf.d/matrix-synapse.conf.j2

@@ -372,6 +372,16 @@ server {
 			{% endfor %}
 			# FIXME: add GET ^/_matrix/federation/v1/groups/
 		{% endif %}
+		{% if media_repository_workers %}
+			# https://github.com/matrix-org/synapse/blob/master/docs/workers.md#synapseappmedia_repository
+			{% for location in matrix_nginx_proxy_synapse_media_repository_locations %}
+			location ~ {{ location }} {
+				proxy_pass http://media_repository_upstream$request_uri;
+				proxy_set_header Host $host;
+				proxy_set_header X-Forwarded-For $remote_addr;
+			}
+			{% endfor %}
+		{% endif %}
 	{% endif %}
 
 	location / {