Add gitea role

Added base gitea docker setup role.

Adds automatic unattended setup with default admin account and optional
email notification setup.

roles/gitea/README.md

@@ -0,0 +1,41 @@
+# gitea
+
+A relatively light-weight git server hosting.
+
+## Defaults
+
+```
+gitea_upstream_file_dir: "{{ docker_stack_files_dir }}/{{ stack_name }}"
+```
+
+The on-target directory where the proxy configuration file should be stashed.
+
+```
+gitea_use_https: true
+```
+
+Whether the service should be reachable through http (port 80) or through https (port 443) and provision an https certificate. Usually you will want this to stay `true`.
+
+```
+gitea_version: latest
+```
+
+The docker image version to be used in stack creation.
+
+```
+subdomain_alias: git
+```
+
+If the deployed container should be served over a uri that is not the stack name. 
+By default, it will be set to `git.yourdomain.com` - 
+if this option is not set it will be served on `gitea.yourdomain.com` instead.
+
+For now gitea will still need to be initially set up after installation.
+This could be automated with the help of these commands:
+
+```sh
+docker run --name gitea -p 8080:3000 -e GITEA__security__INSTALL_LOCK=true -d gitea/gitea:1.14.2
+
+$ docker exec gitea migrate
+$ docker exec gitea gitea admin user create --admin --username root --password admin1234 --email admin@example.com
+```