Adding PhasedQubitSparsePauli and PhasedQubitSparsePauliList

[DanPuzzuoli]

Summary

This PR adds PhasedQubitSparsePauli and PhasedQubitSparsePauliList. These classes are very similar in motivation/functionality as QubitSparsePauli and QubitSparsePauliList (which are phase-less), but for the case where we want to store the phases of the Paulis.

The phases in PhasedQubitSparsePauli and PhasedQubitSparsePauliList will be stored in the same format as Pauli:

• Internally the ZX-phase is stored, but the phase attribute will return the "group phase". E.g. Pauli("Y")._phase == 1 (as Y = ((-i)^1)ZX, whereas Pauli("Y").phase == 0.

Details and comments

At this stage, the PR is setting up some basic functionality for PhasedQubitSparsePauli, and defines an extremely minimal PhasedQubitSparsePauliList.

[coveralls]

Pull Request Test Coverage Report for Build 16377058382

Details

• 191 of 448 (42.63%) changed or added relevant lines in 3 files are covered.
• 15 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.2%) to 87.543%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
crates/quantum_info/src/pauli_lindblad_map/phased_qubit_sparse_pauli.rs	160	417	38.37%

Files with Coverage Reduction	New Missed Lines	%
crates/circuit/src/symbol_expr.rs	3	73.73%
crates/qasm2/src/lex.rs	6	91.75%
crates/qasm2/src/parse.rs	6	97.09%

Totals
Change from base Build 16327707788:	-0.2%
Covered Lines:	81644
Relevant Lines:	93262

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💛 - Coveralls