Complete estimation of proof security level

[bobbinth]

Proof security level estimation currently takes into account only trace security level. This is incomplete as it does not incorporate security level of low-degree testing. This should be fixed.

Security level is currently estimated here: https://github.com/GuildOfWeavers/distaff/blob/master/src/stark/options.rs

It might make sense to do this after #1 is addressed.