This PR refactors the state_transition file. This was to make it easier to maintain this code and bring future changes and updates. I'm deriving this from my experience working on rollup-geth and implementing various EIPs/RIPs such as EIP-7706

I tried to make this PR small so that it's easy to review and give feedback on whether you like these changes.
The general overview of the PR:

1. There is a lot of gas handling logic, all of which has been moved to state_transition_gas.go
2. I have extracted hardfork-specific stuff to separate functions, e.g., preCheckGasLondon. The benefit of this is that the logic is well contained, the caller functions are smaller, and it'll be easier to add new hardfork logic in the future
3. Some functions could've been split even further, but I didn't want to overkill it 😅
4. I haven't changed the flow of the logic, nor added any new features
5. All tests pass

P.S.
I've opened the PR from personal fork instead from rollup-geth fork, as it was easier for me to do so.