feat(nargo): print-acir command

[joss-aztec]

Related issue(s)

Resolves #1030

Description

Summary of changes

Adds the ability to print a compiled circuit to stdout such that the ACIR can be inspected.

aztec@Aztecs-MBP pedersen % nargo print-acir
current witness index : 6
public input indices : [2, 4]
EXPR [ (1, _1) (2, _2) (-1, _3) 0 ]
BLACKBOX::PEDERSEN [(_1, num_bits: 254), (_2, num_bits: 254), (_3, num_bits: 254)] [ _4, _5]

Checklist

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt with default settings.
• I have linked this PR to the issue(s) that it resolves.
• I have reviewed the changes on GitHub, line by line.
• I have ensured all changes are covered in the description.

Documentation needs

• This PR requires documentation updates when merged.

It's a new feature that could be made known to devs as it's very useful for education.

[jfecher]

Fairly straightforward