Feature: Allow authentication via API Credentials

[siddharthlatest]

Currently, we only support authentication via a user token (which is based on a cookie). We are in the process of opening up the Accounts APIs (cc @utsavoza) where we would like any user to access the endpoints present alternatively without using a token.

We can add this support in the CLI itself by offering:

abc login api <username:password>

which will login the user using their master API credentials, cc @utsavoza.

[siddharthlatest]

@palash25 Has this already been implemented or is remaining to be?

[octate]

@palash25 if this is not yet implemented, we can come again on this.
@jeet-parekh, let's put this on priority after we are done with verified issues. I will point you to the specifications of basic authentication.

[palash25]

@raazcrzy I had a WIP commit for this that I had forgotten to push. I have made the PR and pinged you there, please take a look.