Replace burning gas logic in CanonicalTransactionChain

[elenadimitrova]

The OVM_CanonicalTransactionChain.enqueue() function currently burns through 1/32th of the gasLimit the cross domain message is sent with. This gas represents the "L2 fee" and thus instead of burning it, should be distributed accordingly.

Additional context
This was also discussed in the context of reducing the cost of deposit here
#667 (comment)

[snario]

Warrants larger discussion cc @ben-chain

[smartcontracts]

I think this would be a good topic for a GH discussion.

[smartcontracts]

Discussion is here now: ethereum-optimism/optimistic-specs#32