Refactor MongoDB connection in Streamlit app to use environment variable for URI instead of secrets, improving flexibility for deployment.

Refactor Streamlit app to integrate MongoDB connection and enhance data loading features. Added user interface elements for selecting sites, slates, and stack analysis options. Implemented position validation for player combinations and added CSV export functionality for stack options.

Enhance Dockerfile to expose secret for git remote URL and update requirements.txt with additional dependencies including gspread, openpyxl, matplotlib, pymongo, pulp, docker, plotly, and scipy.

initial commit

Duplicate from streamlit/streamlit-template-space