remove vestigial function calculating squeeze angle

Removed the function sqzOptimalSqueezeAngle from quantum.py which is supposed to calculate the squeeze angle as a function of frequency. It is no longer used, wasn't great to begin with, and is causing confusion for other users looking at the code. (It also has a bug if it were to be resurrected.) This is calculated correctly on superQK and will eventually be returned in a more user friendly way than sqzOptimalSqueezeAngle ever worked.