Clean up process package fns, enable mypy

[amrit110]

PR Type ([Feature | Fix | Documentation | Test])

Refactor

Short Description

• Enable mypy for process package and fix typing issues
• Remove column names and functions that acted on specific columns to improve generalizability

Tests Added

...

[codecov]

Codecov Report

Merging #505 (f75f508) into main (aee3f78) will decrease coverage by 0.35%.
The diff coverage is 90.08%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #505      +/-   ##
==========================================
- Coverage   63.70%   63.36%   -0.35%     
==========================================
  Files          96       95       -1     
  Lines        9409     9315      -94     
==========================================
- Hits         5994     5902      -92     
+ Misses       3415     3413       -2     

Files	Coverage Δ
cyclops/process/clean.py	95.55% <100.00%> (+1.65%)	⬆️
cyclops/process/constants.py	100.00% <100.00%> (ø)
cyclops/process/diagnoses.py	79.41% <100.00%> (-0.59%)	⬇️
cyclops/process/feature/handle_types.py	79.91% <100.00%> (ø)
cyclops/process/feature/normalize.py	86.98% <100.00%> (ø)
cyclops/process/feature/split.py	98.87% <100.00%> (ø)
cyclops/process/feature/vectorized.py	67.43% <100.00%> (ø)
cyclops/process/impute.py	80.39% <100.00%> (ø)
cyclops/process/string_ops.py	91.80% <100.00%> (ø)
cyclops/process/util.py	100.00% <100.00%> (+1.44%)	⬆️
... and 3 more