Entrypoint for EVM circuit and specification for BEGIN_TX

[han0110]

This PR aims to:

• Provide a entrypoint verify_steps to better describe EVM circuit.
• Naively setup all used lookup tables' interface (except keccak256_table).
• Naively enumerate all possible execution result. (resolves EVM errors  #29)
• Spec BEGIN_TX to verify the beginning of a transaction.
• Implement ADD and PUSH using newly introduced Instruction as sample code.
• Take is_code annotation for JUMP* #66 into consideration in bytecode_table for further implementation.

Some changes have been made including:

• Bus mapping is split into multiple tables corresponding their provider. In the end we can still merge them into same lookup table with some selector, but it depends on the dimension and desired capacity.
• global_counter is renamed to rw_counter cause only writable data are time-aware.
• Error cases is separated from success cases to avoid redundant implementation and test. See ExecutionResult for all possible cases.
• Introduce Instruciton to simulate both verifier (constrain some relation) and prover (calculate some non-qudratic relation).

[gaswhat]

My concern is that the allocations in each Step is quite difficult to write for the test cases in the current way. For a stack push/pop, you need to manually set the lookup entry. Is it possible that we could mimic the approach in the circuit repo that separates the execution steps from the bus mapping lookup?

[ChihChengLiang]

I did not give a thorough look, just reading through the previous review discussions. If there's nothing more to add to this PR, we can merge and unblock the future PR.

[DreamWuGit]

LGTM!

[han0110]

Merge for unblocking further PRs.