MAIN TASK: Performance improvements

[scout-mckee]

• Use a binary format for loading data faster
• Have no redundant filtering/mutating of the data in the app
• Create a processed data file that is loaded in the app instead (stored in data/processed).
• Have no excessively slow computation that could be easily sped up, e.g. no row-wise use of apply unless well justified and optimized.
• Use caching for at least one function

[riyaeliza123]

Binary format done #138

[riyaeliza123]

caching done #167