Clean up `PyQrackReg` implementation

[weinbe58]

Clean up implementation using list as a base class.

Originally posted by @weinbe58 in #152 (comment)

[weinbe58]

could be implemented when fixing #160

[weinbe58]

from my discussion with @david-pl

I would like to refactor PyQrackReg to be a container of PyQrackQubit's

Currently each PyQrackReg contains a list tuple of integeters addrs which correspond to the qubit id inside the QrackSimulator object that is generated by the MemoryABC.allocate API.

The new class for PyQrackReg should contain

1. refactor the PyQrackQubit the QrackSimulator's address for that qubit currently stored inside of PyQrackReg as addrs
2. reference to the QrackSimulator object which I have called
3. The atom state enum

After this the PyQrackReg object can simply be a container of PyQrackQubit's. After this refactoring we should consider trying to fix #162 replacing the QReg class and QRegType with an IList of Qubits like what is currently being done in Squin.

cc: @Roger-luo

[Roger-luo]

I'm wondering how would this work when we work with squin and the qubit.new returns IList[Qubit]? We will have an IList[PyQrackQubit]? then should we just make the runtime of a register a IList[PyQrackQubit]?

[weinbe58]

Yes that's exactly the idea