Add self-contained Gitea Git service with PostgreSQL integration

- Implements complete Gitea Git service following rick-infra self-contained architecture
- Uses PostgreSQL infrastructure role as dependency and manages own database/user
- Native Arch Linux installation via pacman packages
- Automatic database setup (gitea database and user creation)
- SystemD service with security hardening and proper dependency management
- Caddy reverse proxy integration deployed to sites-enabled directory
- SSH server on port 2222 with automatic host key generation
- Production-ready with LFS support, security headers, and HTTPS via Caddy
- Follows simplified configuration approach with essential variables only
- Self-contained pattern: service manages complete setup independently

roles/gitea/templates/app.ini.j2

@@ -0,0 +1,60 @@
+# Gitea Configuration - Rick-Infra
+# Generated by Ansible Gitea role
+
+[DEFAULT]
+APP_NAME = {{ gitea_app_name }}
+RUN_MODE = {{ gitea_run_mode }}
+
+[repository]
+ROOT = {{ gitea_home }}/repositories
+DEFAULT_BRANCH = {{ gitea_default_branch }}
+
+[server]
+PROTOCOL = http
+DOMAIN = {{ gitea_full_domain }}
+HTTP_PORT = {{ gitea_http_port }}
+ROOT_URL = https://{{ gitea_full_domain }}/
+DISABLE_SSH = false
+START_SSH_SERVER = {{ gitea_start_ssh_server | lower }}
+SSH_DOMAIN = {{ gitea_full_domain }}
+SSH_PORT = {{ gitea_ssh_port }}
+SSH_LISTEN_PORT = {{ gitea_ssh_port }}
+LOCAL_ROOT_URL = http://127.0.0.1:{{ gitea_http_port }}/
+APP_DATA_PATH = {{ gitea_home }}/data
+
+[database]
+DB_TYPE = {{ gitea_db_type }}
+HOST = {{ gitea_db_host }}:{{ gitea_db_port }}
+NAME = {{ gitea_db_name }}
+USER = {{ gitea_db_user }}
+PASSWD = {{ gitea_db_password }}
+SSL_MODE = disable
+CHARSET = utf8
+
+[security]
+INSTALL_LOCK = true
+SECRET_KEY = {{ ansible_machine_id }}{{ gitea_db_password | hash('sha256') }}
+INTERNAL_TOKEN = {{ (ansible_machine_id + gitea_db_password) | hash('sha256') }}
+
+[service]
+DISABLE_REGISTRATION = {{ gitea_disable_registration | lower }}
+REQUIRE_SIGNIN_VIEW = {{ gitea_require_signin | lower }}
+DEFAULT_KEEP_EMAIL_PRIVATE = true
+DEFAULT_ALLOW_CREATE_ORGANIZATION = true
+NO_REPLY_ADDRESS = noreply.{{ gitea_domain }}
+
+[log]
+MODE = console
+LEVEL = Info
+ROOT_PATH = {{ gitea_home }}/log
+
+{% if gitea_enable_lfs %}
+[lfs]
+START_SERVER = true
+CONTENT_PATH = {{ gitea_home }}/data/lfs
+{% endif %}
+
+[git]
+PATH = /usr/bin/git
+
+# Rick-Infra: Simplified Gitea configuration for self-contained service