Fix "src/" files to adhere to BIDS and get rid of unnecessary code

[adam2392]

Describe the bug
Project, Subject, Block are all really weird interfaces right now. We should improve it to make them easily Bids compliant and an easy function to extract the necessary data from each. "Necessary data" can be gleaned from the original paper.

Project should trim all the unnecessary data and just use mne-bids to be compliant easily.

Lines like this should be reformatted using mne_bids.make_bids_basename:

                f"sub-{params['sub']}",
                f"ses-{params['ses']}",

Subject seems to be doing things that can be inferred from mne-bids.

_parse_bids_filename, and easy utility functions. Having a class f

Expected behavior
A clear and concise description of what you expected to happen.

Additional context
Add any other context about the problem here.