Update rebuilderd to 0.3.0

Adjust the configuration of rebuilderd and change the proxy pass port to
the new default port 8484. Remove the plaintext from nginx as it now
serves a nice html website.

roles/rebuilderd/tasks/main.yml

 - name: install required packages
   pacman: name=rebuilderd state=present
 
-# TODO: remove when repro is released with https://github.com/archlinux/archlinux-repro/pull/73
-- name: import bootstrap gpg key
-  command: gpg --auto-key-locate nodefault,wkd --locate-keys pierre@archlinux.de
-
 - name: create ssl cert
   command: certbot certonly --email webmaster@archlinux.org --agree-tos --rsa-key-size 4096 --renew-by-default --webroot -w {{ letsencrypt_validation_dir }} -d '{{ rebuilderd_domain }}' creates='/etc/letsencrypt/live/{{ rebuilderd_domain }}/fullchain.pem'
   when: 'rebuilderd_domain is defined'

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

@@ -26,13 +26,9 @@ server {
     ssl_certificate_key  /etc/letsencrypt/live/{{ rebuilderd_domain }}/privkey.pem;
     ssl_trusted_certificate /etc/letsencrypt/live/{{ rebuilderd_domain }}/chain.pem;
 
-    location /api {
-	    proxy_pass http://127.0.0.1:8080;
-    }
+    root /srv/http/repro;
 
-    location / {
-	    access_log off;
-	    default_type text/plain;
-	    return 200 'Arch Linux Rebuilderd Instance https://wiki.archlinux.org/index.php/Rebuilderd';
+    location /api {
+	    proxy_pass http://127.0.0.1:8484;
     }
 }

roles/rebuilderd/templates/rebuilderd.conf.j2

-[http]
-# it is highly recommended to bind to localhost and setup nginx as a reverse proxy for https
-bind_addr = "127.0.0.1:8080"
-
-[auth]
-# set the generated secret for administration here
-#cookie = "{{ vault_rebuilderd_auth_cookie }}"
-
 [worker]
 # set the generated secret for our workers here
 signup_secret = "{{ vault_rebuilderd_signup_secret }}"