Add OpenAPI-based API documentation and new endpoints

Integrated OpenAPI and Swagger plugins for comprehensive API documentation. Added new routes, including settings management (`/settings/*`), guild metadata endpoints (`/guilds/*`), and detailed action status handling. Updated database schema to support guild metadata persistence, revised command subcommand handling for better modularity, and enhanced API key-based authentication for all routes.

.env.example

@@ -5,6 +5,7 @@ NETNEUTRALITY_BOT_PREFIX=$
 NETNEUTRALITY_BOT_OWNER=
 NETNEUTRALITY_BOT_INVITE=
 NETNEUTRALITY_API_PORT=9000
+NETNEUTRALITY_API_KEY=
 
 MYSQL_HOST=127.0.0.1
 MYSQL_PORT=3306