Issue #367 - Migration from QasmSimulator to qiskit_aer's AerSimulator

[robotAstray]

Summary:

This PR addresses issue #367 by implementing changes across various files in the codebase. The changes involve the migration from qiskit.Aer to qiskit_aer, replacement of QasmSimulator with AerSimulator, and the introduction of PadDynamicalDecoupling. Additionally, the PR requires the use of ALAPScheduleAnalysis within the PassManager

Details and comments:

The following files have been modified as part of this PR:

• src/qiskit_qec/analysis/faultenumerator.py
• src/qiskit_qec/analysis/faultsampler.py
• src/qiskit_qec/circuits/repetition_code.py
• test/code_circuits/test_rep_codes.py
• test/heavy_hex_codes/test_heavy_hex_decoder.py
• test/matching/test_circuitmatcher.py
• test/matching/test_repetitionmatcher.py

Key Changes:

• Migration from qiskit.Aer to qiskit_aer,
• Migration from from QasmSimulator to AerSimulator
• Introduction of PadDynamicalDecoupling, which requires the use of ALAPScheduleAnalysis in PassManager.

[robotAstray]

@grace-harper this PR is ready for review :+1:

[robotAstray]

Hello @grace-harper the errors are related to a bug I identified and described in issue #380. I do not think is related to the work I did on issue #367.