Remove nargo info command

[TomAFrench]

We want bb to be able to ingest a directory of ACIR build artifacts and spit out a JSON formatted report similar to that used by noir-lang/noir-gates-diff. The human readable output can be a bit rough and ready (i.e. just print out a line for each circuit with the relevant data rather than a pretty table) as a first cut.

Success looks like us being able to replace the current workflow with a combo of the three commands:

nargo compile
bb info
<feed json into github action>

[TomAFrench]

This is completed now.