Improve js/python interface

Currently, the interface between python and js is quite unacademic, and highly relies on the order of parameters. This is not very robbust to any error in the transmitted parameters, as well as the order. Furthermore, we have to rely on parameter order, which can easily lead to errors, with tough debugging).

Using a purely CLI interface, with options parsed with python lib argparse would make things easier to manage, evolve, maintain, and to debug. In a way this should be better.

For exemple, transation fetch could be done with :

main.py operations --bank fakebank --username myname --password mysupersafepassword (--debug) (--customfields "mystringifiedJSONCustomFields")

We could also add an option --update-first to more easily handle #662 (closed)