[contracts] Derive useful traits for public types

[pmikolajczyk41]

Description

We add a few derivations to the public types from pallet-contracts and pallet-contracts-primitives crates. While they are not used directly in the runtime (and thus the implementation code will be pruned by a compiler), they would be very useful for contracts-related tooling. Also, this brings a bit more consistency to these libraries' public API (e.g. schedule module has already all its public types enriched with many similar trait derivations).

Checklist

• My PR includes a detailed description as outlined in the "Description" section above
• My PR follows the labeling requirements of this project (at minimum one label for each A, B, C and D required)
• I have made corresponding changes to the documentation (if applicable)
• I have added tests that prove my fix is effective or that my feature works (if applicable)
• If this PR alters any external APIs or interfaces used by Polkadot, the corresponding Polkadot PR is ready as well as the corresponding Cumulus PR (optional)

[ascjones]

bot merge