Rate limit our archweb RSS feeds

Due to users misconfiguring their conky to query for rss updates every
second add proper rate limitting to all rss endpoints in nginx.

roles/archweb/templates/nginx.d.conf.j2

+# limit rss requests to 1 r/m
+limit_req_zone $binary_remote_addr zone=rsslimit:8m rate=1r/m;
+limit_req_status 429;
+
 upstream archweb {
     server unix:///run/uwsgi/archweb.sock;
 }
@@ -169,6 +173,14 @@ server {
         alias {{ archweb_retro_dir }};
     }
 
+    # Rate limit all RSS feeds
+    location ~ (^/feeds/|\.xml$) {
+        include uwsgi_params;
+        uwsgi_pass archweb;
+
+        limit_req zone=rsslimit burst=10 nodelay;
+    }
+
     location / {
         access_log   /var/log/nginx/{{ archweb_domain }}/access.log main;
         include uwsgi_params;