chore: remove Alembic migration files and related configurations

- Deleted Alembic migration files and configuration to streamline the project and eliminate unused components.
- Updated documentation to reflect the removal of distributed operations coordination from Redis.
- Removed references to Alembic in the requirements and project structure, simplifying the database management approach.

Author: atyrode

docs/context.md

@@ -64,7 +64,6 @@ The system follows a microservices architecture with the following components:
 3. **Redis**
    - Manages user sessions
    - Provides caching for performance
-   - Coordinates distributed operations (like migrations)
 
 4. **Keycloak**
    - Provides OIDC authentication