Estimates comparing a mithril chain using current certificates with a mithril chain using Groth16 + SNARK-Pack

## Why
In a discussion with @curiecrypt , the possible usage of SNARK-Pack for mithril came up as something potentially interesting. As an exploratory process, it would be interesting to have some numbers comparing the performance of a Mithril chain using existing certificates with one using Groth16 + SNARK-Pack

## What
Perform some estimates using the benchmarks of the original [paper](https://eprint.iacr.org/2021/529.pdf), and compare such estimates with the current benchmarks we have of Mithril.