Hardening proxy settings: prevent default page from libravatar

This patch should prevent the libravatar default page from being
proxied. As well as preventing libravatar.org from being an entrence for
external JS into the libravatar-nginx domain.

default.conf

@@ -72,12 +72,25 @@ server {
         proxy_set_header User-Agent: "'Mozilla/5.0 (compatible; Libravatar-nginx/2.2.0; +https://git.shivering-isles.com/shivering-isles/libravatar-nginx)'";
 
         proxy_http_version 1.1;
-        proxy_pass https://seccdn.libravatar.org;
 
+
+        location /libravatarproxy/avatar/ {
+          proxy_pass https://seccdn.libravatar.org/avatar/;
+          proxy_redirect default;
+          proxy_redirect /avatar/ /libravatarproxy/avatar/;
+          proxy_redirect /static/img/ /libravatarproxy/static/img/;
+          proxy_redirect /gravatarproxy/ /libravatarproxy/gravatarproxy/;
+        }
+
+        location /libravatarproxy/static/img/ {
+          proxy_pass https://seccdn.libravatar.org/static/img/;
           proxy_redirect default;
-        proxy_redirect / /libravatarproxy/;
-        #proxy_redirect https://seccdn.libravatar.org/avatar/ /libravatarproxy/avatar/;
-        #proxy_redirect https://seccdn.libravatar.org/static/ /libravatarproxy/static/;
+        }
+
+        location /libravatarproxy/gravatarproxy/ {
+          proxy_pass https://seccdn.libravatar.org/gravatarproxy/;
+          proxy_redirect default;
+        }
     }
 
     location @defaultimage {