feat: add Address type

[m62624]

Resolves #1262

[gemini-code-assist]

Code Review

This pull request introduces a new Address type to support Solidity-compatible address handling and updates the Solidity contract generator to recognize custom types annotated with @sol_type. The changes include the implementation of the Address struct with relevant traits for ABI encoding and various type conversions, alongside updates to the generator's type resolution logic. Feedback indicates that the current type resolution for @sol_type annotations is limited to top-level named types and should be implemented recursively to support collections such as arrays and slices.