Methods for GPI, GPI2, and AAMS gates.

[michaelontiveros]

Description

1. Fix GPI2 in pytket (a typo in the binder would cause c.GPI2 to return c.GPI).

2. Add symbolic GPI, GPI2, and AAMS gates.

3. Add methods to decompose the following gates to GPI, GPI2, and AAMS:
   -Rx, Ry, Rz,
   -XXPhase, YYPhase, ZZPhase,
   -TK1, TK2.

4. Support the target gateset (GPI, GPI2, AAMS) in the auto_rebase_pass.

5. Add the transform rebase_ionq. It decomposes the gates in the source circuit to the IonQ native gateset (GPI, GPI2, AAMS). It does not push the Rz's in the source circuit to the end of the target circuit using commutation relations with the target gates.

Related issues

Resolves #1361.

Checklist

• I have performed a self-review of my code.
• I have commented hard-to-understand parts of my code.
• I have made corresponding changes to the public API documentation.
• I have added tests that prove my fix is effective or that my feature works.
• I have updated the changelog with any user-facing changes.

[cqc-alec]

Thanks! Please could you also add a method to convert a CX gate, and add some C++ tests to get the coverage up? Otherwise looks great.

[michaelontiveros]

I added CX_using_AAMS(), and changed the rebase pass to use it instead of TK2_using_AAMS().
I added CircPool and Symbolic tests.

[cqc-alec]

Thank you for your work on this.

[michaelontiveros]

My pleasure.