Create style/standards guide for cdapython UI

[abradyGDIT]

• First item: on an error caught within any function in the cdapython package:

  • Is the calling entity one of our functions?
    • Yes: raise error object to caller
  • Is the calling entity a user (e.g. get_subject_data())?
    • Yes: print human-readable error message and return

• Once documented: review existing cdapython code to ensure universal compliance

[abradyGDIT]

@self see also manila folder "FUTURE/SDLC"