Binary arithmetic gates

[Cryoris]

Summary

Part of #13046: gate representations & plugins for the binary arithmetic operations (adder and multiplier).

[qiskit-bot]

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

• @Cryoris
• @Qiskit/terra-core
• @ajavadia

[coveralls]

Pull Request Test Coverage Report for Build 11707625761

Details

• 298 of 327 (91.13%) changed or added relevant lines in 17 files are covered.
• 4 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.003%) to 88.786%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
qiskit/synthesis/arithmetic/adders/draper_qft_adder.py	25	26	96.15%
qiskit/synthesis/arithmetic/multipliers/hrs_cumulative_multiplier.py	24	26	92.31%
qiskit/synthesis/arithmetic/multipliers/rg_qft_multiplier.py	22	24	91.67%
qiskit/circuit/library/arithmetic/adders/adder.py	28	31	90.32%
qiskit/circuit/library/arithmetic/multipliers/multiplier.py	18	21	85.71%
qiskit/transpiler/passes/synthesis/hls_plugins.py	61	79	77.22%

Files with Coverage Reduction	New Missed Lines	%
crates/qasm2/src/lex.rs	4	92.73%

Totals
Change from base Build 11706516151:	-0.003%
Covered Lines:	77319
Relevant Lines:	87085

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💛 - Coveralls

[alexanderivrii]

I really like this PR. I have left several comments in-place.

Now the follow-up step is to port the synthesis functions to Rust :).

[alexanderivrii]

Thanks for making all these changes!