Allow querying the gates in a Program in a single request

[TomAFrench]

Migration of noir-lang/noir#4851

See noir-lang/noir#4962

aztec-packages/barretenberg/cpp/src/barretenberg/bb/main.cpp

Lines 295 to 312 in ed84fe3

	/**
	* @brief Computes the number of Barretenberg specific gates needed to create a proof for the specific ACIR circuit
	*
	* Communication:
	* - stdout: The number of gates is written to stdout
	*
	* @param bytecodePath Path to the file containing the serialized circuit
	*/
	void gateCount(const std::string& bytecodePath)
	{
	auto constraint_system = get_constraint_system(bytecodePath);
	acir_proofs::AcirComposer acir_composer(0, verbose);
	acir_composer.create_circuit(constraint_system);
	auto gate_count = acir_composer.get_total_circuit_size();
	writeUint64AsRawBytesToStdout(static_cast<uint64_t>(gate_count));
	vinfo("gate count: ", gate_count);
	}

We want to be able to query the number of constraints in a multi-circuit program in a single go. It should also be easy to generate a report for a whole workspace of programs.

[TomAFrench]

@vezenovm assigning you to this as you've been working on the noir-gates-diff action as well. Ideally the bb gates command should respond with the same json format we're using to feed into the action.

We can have a nice human readable report later on (making ASCII formatting in c++ 🤮).