[CHECKLIST] Improve Documentation

[1xstj]

Overview

The goal is to improve the state of documentation and README in general

Checklist

For every crate/pallet we should

• [ ] Add a README with an overview on what the crate/pallet does and how to use/test it
• [ ] Improve rust docs where possible

Crates

• [ ] Dkg-metadata
• [ ] dkg-proposals
• [ ] dkg-proposal-handler
• [ ] dkg-gadget
• [ ] dkg-orchestrator
• [ ] dkg-logging
• [ ] dkg-mock-blockchain
• [ ] dkg-test-suite

[drewstone]

Possible useful tool: https://docs.rs/cargo-readme/latest/cargo_readme/