Refactor streamlit_web.py

[enpuyou]

streamlit_web.py is the entry point of the project/the web interface. There are currently no test cases for the file; it is also not being counted in the test coverage. The file itself contains a lot of data processing and cleaning. It also calls the functions from all the submodules, including visualization.py.

To some extent, this monolith module contains an enormous amount of complexity. It is hard to test or continue developing, especially for someone who's not familiar with the codebase. A good starting point is to refactor this module, variable naming, data processing, better abstraction, docstring, etc. It could be an intractable problem that requires extra carefulness.