Tidy assets and package data

[sr-murthy]

The assets folder (assets) is too big and unstructured - most files are images (PNG) which could be moved to an images subfolder, while the rest can remain in their existing subfolders. The new CRF metadata CSV can go into a crf subfolder. CRF metadata CSV to go into ARC.

Package data inclusion in the TOML is too broad - currently, the release files contain every non-Python file in the repository, including cloud deployment files such as replit.nix, the hidden Git ignore file, the .coveragerc file which should always be local, and also all test files. Packages (source distributions as ZIP or tarballs, or wheels if wheels were ever to be distributed) should only include real package assets.

[EstebanGarciaG]

The new CRF metadata should be in the ARC repository. It could be a file (like a csv) that is updated 1) before each new ARC release 2) manually when information is added to a record of an old CRF.

[sr-murthy]

OK, that makes sense.

The ARC PR to add the metadata CSV. The one I've added for the moment is purely for testing, but we should aim to have a final version included in the PR.