[Gas Mechanism] Gas metering for module verification during publish

[lxfind]

Some module verification passes can take non-linear time to finish. We currently charge publish based on the number of bytes. But for those non-linear passes (e.g. anything that uses abstract interpretation), we should do some kind of metering (doesn't need to accurate, just need to be deterministic across validators) for this.

[bholc646]

Need to discuss further and decide on a solution

[oxade]

Decided on flat fee