feat: Deploy server and runners independently

Signed-off-by: Julien Riou <julien@riou.xyz>

defaults/main.yml

@@ -1,4 +1,5 @@
 ---
+forgejo_server: true
 forgejo_version: 11
 forgejo_home_dir: /var/lib/forgejo
 forgejo_config_dir: /etc/forgejo
@@ -11,6 +12,7 @@ forgejo_manage_iptables: false
 forgejo_allowed_sources: []
 forgejo_runners_version: 9.1.1
 forgejo_runners_config_dir: /etc/forgejo-runners
+# forgejo_runners_instance:
 # forgejo_runners:
 #   repository: token
 forgejo_runners: {}