feat: Implement generic EVM->EVM transfers

[saadjhk]

Following the proposed v3 SDK restructure, implement/restructure the necessary functions for creating GMP (General Message Passing) deposit transactions on EVM networks.

Implementation details

Check packages/evm/src/generic.ts for the interface definitions.

Testing details

• Restructure and update existing unit tests (expand if required)
• Validate manually that refactored evm-to-evm-generic-message-example is passing on testnet

QA Details

• New exposed interfaces and functions should allow the same functionalities as the v2 SDK implementation, such as creating GMP transfers and estimating fees.

Acceptance Criteria

• [x] Implementing EVM GMP transfers following v3 guidlines
• [x] Restructure and update existing unit tests
• [x] Update evm-to-evm-generic-message-example example to use v3 implementation
• [x] Validate evm-to-evm-generic-message-example example manually on testnet

Closes

373