Refactor hardhat_, evm_, and zks_ namespace implementations

[nbaztec]

📝 Description

Refactor the hardhat_, evm_, and zks_ namespace implementations for some functions to be stored in a centralized location, so they can be re-used accordingly.

For example, the following endpoints are doing the same thing:

• evm_setAccountNonce
• hardhat_setNonce
• anvil_setNonce

🤔 Rationale

Centralizing namespaces would lead to a significantly lower effort for contributors implementing other namespaces and/or methods.

📋 Additional Context

This is a prerequisite for #160