Enhance Telegram bot with database integration and API features

- Added SQLite database support with Alembic for migrations.
- Implemented FastAPI for HTTP API to manage duties.
- Updated configuration to include database URL and HTTP port.
- Created entrypoint script for Docker to handle migrations and permissions.
- Expanded command handlers to register users and display duties.
- Developed a web application for calendar display of duties.
- Included necessary Pydantic schemas and SQLAlchemy models for data handling.
- Updated requirements.txt to include new dependencies for FastAPI and SQLAlchemy.

.env.example

@@ -1 +1,4 @@
 BOT_TOKEN=your_bot_token_here
+DATABASE_URL=sqlite:///data/duty_teller.db
+MINI_APP_BASE_URL=
+HTTP_PORT=8080