Merge fastapi-integration into main

[ByteBard58]

• Refactor project structure and move app-specific files to the newly created /app subdirectory
• Rename older flask-powered app script and create new one for fastapi
• Add primary self-heal function and configuration in app.py and add BaseModel class in schema for validation
• Add fully configured pydantic BaseModel for input validation on /predict route
• Update requirements.txt to add fastapi and other dependencies
• Add /about,/predict and /predict/batch endpoints for both regular and batch prediction to app.py
• Add sample generator script and modify .gitignore to ignore generated sample CSV files
• Fix typo in docstring of sample_generator.py
• Debug some issues in app.py,
• Modify path filtering configuration in the CI scripts
• Replace older gunicorn setup with uvicorn for fastapi
• Update the dependency list by getting rid of no-longer required libraries
• Delete older flask-based app
• Link the existing vanilla frontend with the fastapi app, implement notification system and improve error handling for form submissions
• Enhance UI with tab navigation, batch prediction functionality, and improved button styles
• Implement integration test suite with FastAPI TestClient and model mocking