feat: add Docker support and bot configuration

- Introduced Dockerfile for building the bot application using Go.
- Added .dockerignore to exclude unnecessary files from the Docker context.
- Updated docker-compose.yml to define the bot service and its dependencies, including environment variables for database and Lavalink configuration.
- Modified internal configuration to streamline environment variable handling.

.dockerignore

@@ -0,0 +1,7 @@
+.git
+.gitignore
+.env
+*.md
+Dockerfile
+docker-compose*.yml
+.dockerignore