Modify for USA, refactor for NLTK and create a USA

[ripnyt-ripnyt]

added _read_usbank_file, _read_boa_file (Bank of America), and a partial _read_blockfi_file. Blockfi data requires collapsing prior to being read into this. I had already done some pre processing. Still need to add _read_chase_file.

refactored to NLTK since textglob isn't available in standard nixos packages.

my first NLP project! thanks for the template.

[TakesTheBiscuit]

This looks interesting - I'm not a maintainer here but I was wondering if we should chat? I believed it might be time to break the banks out into little importer classes with a consistent interface so that we can import the modules in a more dynamic way in future; for example merges like 'add BOA' would just be a new module into a sub directory. Wondering if @ripnyt-ripnyt or @robintw have a view?

[ripnyt-ripnyt]

Honestly this was my first terminal app and I had fun learning but I don't know enough to have strategic input.