feat: use nginx proxy, config for public rooms (fedi)

See https://git.coopcloud.tech/coop-cloud/matrix-synapse/issues/38.

nginx.conf.tmpl

@@ -0,0 +1,31 @@
+user www-data;
+
+events {
+  worker_connections 768;
+}
+
+http {
+  server {
+    listen 80;
+
+    access_log off;
+    error_log /dev/null;
+
+    server_name {{ env "DOMAIN" }};
+
+    location ~* ^(\/_matrix|\/_synapse\/client) {
+      proxy_pass http://{{ env "STACK_NAME"}}_synapse:8008;
+      proxy_set_header X-Forwarded-For $remote_addr;
+      proxy_set_header X-Forwarded-Proto $scheme;
+      proxy_set_header Host $host;
+      client_max_body_size 50M;
+      proxy_http_version 1.1;
+    }
+
+    location /.well-known/matrix/ {
+      root /var/www/;
+      default_type application/json;
+      add_header Access-Control-Allow-Origin  *;
+    }
+  }
+}