Prepare production readiness for circuit keys and trusted setup in STM

[jpraynaud]

Why

We want to implement production ready support for SRS and circuit keys of SNARK circuits. In particular, we need to define how to cache artifacts (and when to compute it), make sure that circuit verification key is not stale, and prepare work for supporting multiple circuits. Also configuration is a concern that we need to take into consideration.

What

Design the production ready support for circuit keys and trusted setup.

How

• Design production ready support for circuit keys and trusted setup