[Feature]: Optimal Threshold

[sepandhaghighi]

Describe the feature you want to add

Support curves optimal threshold.

Describe your proposed solution

>>> import numpy
>>> from pycm import ROCCurve
>>> crv = ROCCurve(
    actual_vector=numpy.array([1, 1, 2, 2]),
    probs=numpy.array([[0.1, 0.9], [0.4, 0.6], [0.35, 0.65], [0.8, 0.2]]),
    classes=[2, 1])
>>> crv.optimal_threshold
0.5

Describe alternatives you've considered, if relevant

No response

Additional context

No response