Compile noir-contracts with nargo compile

[iAmMichaelConnor]

noir-contracts currently takes silly amounts of ram to compile due to spinning up so many copies of bb at once. I'd recommend switching the shell scripts to just run nargo compile once noir-lang/noir#2612 lands as compilation just takes ~8 seconds on my machine whereas yarn noir:build:all just ends up crashing.

Originally posted by @TomAFrench in #2083 (comment)

[TomAFrench]

This will also remove the need for install_noir_backend.sh (and along with it the need to keep the download URL up to date) as we won't have N different versions of nargo all trying to download bb to the same directory.

One downside is that you won't be able to compile arbitrary subsets of contracts in parallel, it'll be all of them or a single contract, but I don't imagine that would be a dealbreaker.

[Maddiaa0]

Will pick this up now