add `Model` trait

[LimpidCrypto]

High Level Overview of Change

Add a Base trait that brings standard functionalities to all models. The Base trait also adds the get_errors method that checks a model for its unique errors.

Context of Change

7

11

Type of Change

• [x] New feature (non-breaking change which adds functionality)
• [x] Tests (You added tests for code that already exists, or your new feature included in this PR)

Test Plan

TODO

• [x] Add Model to requests
• [x] Add more get_errors
• [x] Add more docstrings to transactions
• [x] Fix get_nftoken_minter_error
• [x] Fix get_nftoken_broker_fee_error
• [x] Fix Transaction.has_flag()
• [x] Fix tests
• [x] Add tests
• [x] Add docstrings

[sephynox]

Rust does not really have a concept of inheritance. Maybe naming it to "Model" might be more appropriate. I see some repetition with the implementation of some of the trait's methods on structs. You can write default implementations in the trait definition and override it when necessary.

[LimpidCrypto]

Rust does not really have a concept of inheritance. Maybe naming it to "Model" might be more appropriate. I see some repetition with the implementation of some of the trait's methods on structs. You can write default implementations in the trait definition and override it when necessary.

Yes, I found that out too. They will be removed with the next commit :) "Model" is definitely a better name.