[WIP] Adding SynthesisData and porting some of the MCX synthesis methods to Rust

[alexanderivrii]

Summary

First, this PR implements the SynthesisData struct, with the goal to simplify porting synthesis algorithms to rust (including synthesis of hierarchical circuits) and standardize the already existing code in crates/accelerate/src/synthesis.

Ideally, we should be using CircuitData instead of introducing SynthesisData, however at the moment CircuitData has a significant overhead. For the sake of an experiment, I have locally rewritten pauli_evolution.rs code, and it became 10x slower when using CircuitData and only 1.1x slower when using SynthesisData. Hopefully we would eventually replace SynthesisData by CircuitData.

To illustrate the above usage of SynthesisData, I am planning to port several MCX synthesis algorithms from Python to Rust. So far:

• synth_c3x

[qiskit-bot]

One or more of the following people are relevant to this code:

• @Qiskit/terra-core

[coveralls]

Pull Request Test Coverage Report for Build 13565454235

Details

• 81 of 141 (57.45%) changed or added relevant lines in 5 files are covered.
• 9 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.05%) to 87.813%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
crates/circuit/src/circuit_data.rs	0	21	0.0%
crates/accelerate/src/synthesis/common/mod.rs	38	77	49.35%

Files with Coverage Reduction	New Missed Lines	%
crates/accelerate/src/unitary_synthesis.rs	1	94.39%
crates/qasm2/src/lex.rs	2	92.48%
crates/qasm2/src/parse.rs	6	97.61%

Totals
Change from base Build 13553732677:	-0.05%
Covered Lines:	77586
Relevant Lines:	88354

---

💛 - Coveralls