Add support for qubit alias decls

[idavis]

This PR sets up the main uses of alias statements for qubit registers.

• Lowers aliasing of qubit and bitarray registers
• Compilation (to Q# ast) fails when used with bitarray registers. This is a known limitation until we decide we want to dig into it. The naive implementation requires reference variables. We can do qubits as they are virtual ids
• Validates type information in lowering raising semantic errors if the aliases aren't type sound.
• There is a stub test case for when we support index sets as part of aliasing