Add function to override default configuration about nkululeko

[felixbur]

the path variable must be unique for the databases, because there can be several databases

[felixbur]

This suggestion reminds me a bit of a functionality i implemented some time ago (probably doesn't work out-of-the-box any more)
https://github.com/felixbur/nkululeko/blob/main/meta/demos/multiple_exeriments/parse_nkulu.py

[bagustris]

For now, it is not a big problem since we can run local test without any change. But it is better to keep this issue open for the future.

[bagustris]

@felixbur
There is a discussion in Stackoverflow exactly related to this matter,

https://stackoverflow.com/questions/48538581/argparse-defaults-from-file

But before going further, I have some things in my head now:

1. User use INI file to define the config (current behavior, simplest).
2. User use command line arguments to override INI file (raised by this issue)
3. User use command line arguments without INI file

Having these capabilities will improve the speed of experimenting with Nkululeko. Just use the arrow key from the terminal to recall the last commands (or history/ctrl-z) and edit the command line arguments to experiment with other variables to see their impact.

[felixbur]

so, 2 is also already implemented
by using the nkuluflag module. An example is here
http://blog.syntheticspeech.de/2022/03/28/how-to-run-multiple-experiments-in-one-go-with-nkululeko/