Merge Transfer and TransferWithGas gadget

Transfer and TransferWithGas gadgets are mostly the same. We can merge them and duplicate them.
There are duplicated logics for creating the receiver account (writing empty hash). We remove the duplicated one.
The update balance gadget is vague, it is hard to understand whether we want to add or subtract balance. We extract a helpful method for that.
deduplicate the transfer_to logic in busmapping.
Fix the receiver creation condition on busmapping.
Fix the order of the sender account read-write in begin tx assignment.

Thank @curryrasul for initializing this conversation.

Refactor (no updates to logic)

cargo test -p zkevm-circuits create
cargo test -p zkevm-circuits begin_tx
cargo test -p zkevm-circuits end_tx

privacy-scaling-explorations / zkevm-circuits