CLI flag support

[rishabhsingh971]

User should be able to pass/set flags through CLI.

[rajatgoyal715]

@rishabhsingh971 Can you please be more specific about the flags here?

[rishabhsingh971]

Any kind of user input script requires, can be a flag just like user config as mentioned here. This is so that script can become one liner instead of requiring user interaction multiple times.

[rishabhsingh971]

IMO, https://pypi.org/project/ConfigArgParse can help us solve both issues, #23 (only the user config) and #24