feat: Allow step debugging inside Brillig blocks

[ggiraldez]

Description

When running the debugger and stepping through a Brillig block, execute each Brillig opcode step by step.

Part of #3015.

Problem

Before this PR, the debugger step command would execute the full Brillig block when stepping through it.

Summary

• Adds support to ACVM to step into a Brillig block suspending execution after each Brillig opcode.
• Adds a new method to ACVM to get the full opcode location to be executed/solved next, also when stepping inside a Brillig block.

Documentation

• This PR requires documentation updates when merged.

  • I will submit a noir-lang/docs PR.
  • I will request for and support Dev Rel's help in documenting this PR.

Additional Context

I'm not 100% happy with the API, especially due to the use of boolean values to distinguish between the two modes of execution, but the resulting code is pretty compact and backwards compatible.

PR Checklist

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[TomAFrench]

Will try to take a look at this today.

[ggiraldez]

This functionality was implemented by #3259 taking a different approach.