Enable full nargo <-> bb.js interop

[vezenovm]

Problem

The current dummy backend in this PR currently only enables someone working with the bb.js backend (found here: https://www.npmjs.com/package/@aztec/bb.js), to compile their circuit and execute a witness into the format that bb.js expects. The current workflow to work with bb.js is to run nargo compile and nargo execute, but then use a global bb.js executable for any proving and verification.

In order to enable using bb.js with nargo we need to add a communication layer for this to be possible. This communication layer is also necessary for us to enable ACVM simulation for black box funcs that need to communicate with the backend (such as pedersen, schnorr, etc.)

Happy Case

nargo should work with bb.js as it does for our plonk_bn254 and plonk_bn254_wasm backends.

Alternatives Considered

No response

Additional Context

With bb.js now including recursion we will have to expose this feature while it will not be supported by our other backends.

Would you like to submit a PR for this Issue?

No

Support Needs

No response

[Savio-Sou]

The kh-nargo-abackend branch enables Nargo <> bb.js interop, works as a transitionary solution to this intermediate issue.

Long term barretenberg and any other proving backends should be packaged into standalone executables with minimum dependencies (versus e.g. bb.js that requires Node.js to run in CLI) and interface with Nargo.

[kevaundray]

Related #595

[Savio-Sou]

@TomAFrench / @kobyhallx can we consider this to be superseded by #2164?

[Savio-Sou]

Superseded by noir-lang/acvm-backend-barretenberg#245, where Noir now interops with bb binary (instead of bb.js).