Common mod near integer and integer multiple of pi code should be refactored

[dabacon]

In convert_to_sqrt_iswap.py we use code to dermine closeness to an integer or a 2 pi times an integer. These helpers appear in a lot in gates and should likely be included in some utility location.

[dabacon]

Alternatively ideas of actual discrete gate sets could be developed which handle these parameter range checking intricacies