r/webites: Add apps.du5t1n.xyz F-Droid repo

I want to publish the _20125_ Status application to an F-Droid
repository to make it easy for Tabitha to install and update.  F-Droid
repositories are similar to other package repositories: a collection of
packages and some metadata files.  Although there is a fully-fledged
server-side software package that can manage F-Droid repositories, it's
not required: the metadata files can be pre-generated and then hosted by
a static web server just fine.

This commit adds configuration for the web server and reverse proxy to
host the F-Droid repository at _apps.du5t1n.xyz_.

group_vars/dch-proxy.yml

@@ -36,6 +36,8 @@ dch_proxy_sites:
 - backend: web
   match: ebonfire.com
   matcher: end
+- backend: web
+  match: apps.du5t1n.xyz
 - backend: web
   match: hatchlearningcenter hlckc hlcks
   matcher: dom

group_vars/public-web/main.yml

@@ -9,6 +9,7 @@ ebonfire_publisher_keys: '{{ dchwww_publisher_keys }}'
 nratonpass_publisher_keys: '{{ dchwww_publisher_keys }}'
 dcow_publisher_keys: '{{ dchwww_publisher_keys }}'
 chmod777_publisher_keys: '{{ dchwww_publisher_keys }}'
+appsxyz_publisher_keys: '{{ dchwww_publisher_keys }}'
 apache_server_name: pyrocufflink.net
 userdir_proxy_backend: http://files.pyrocufflink.blue
 tabitha_publisher_keys: