Update documentation

Complete and format the Rust documentation to ensure the autogenerated documentation includes comprehensive information, especially for public methods, traits, structs, and storage. This will allow downstream developers to refer directly to the documentation without needing to browse the code.

• Incode pallet description: Delete the readme and include pallet documentation directly in the code (another solution would have been #![doc = include_str!("../README.md")], but it is impractical when displaying the source code from the documentation using the "source" tag).
• Document every type.
• Document every storage.
• Document every trait.
• Document every public method.
• Fix #240 (closed).