Clean up repo/add documentation

[Tomserv-512]

Repo contains much more folders than are documented.

Repo structure should be improved and/or documentation updated.

[9600]

Need to coordinate with @enjoy-digital as they work towards a merge of their work.

[enjoy-digital]

It would indeed be appreciated to wait a bit that we merge things to restructure the repo :) We are currently aligning work to use current LimeDFB structure.