Typing mismatch when using Integer/int

[danrr]

Similar to #526, I think there are more places where types should use int|Integer or maybe int|IntegerBase in place of only int or Integer.

I think this is the case at least for:

• random and random_range in https://github.com/Legrandin/pycryptodome/blob/master/lib/Crypto/Math/_IntegerBase.pyi
• __iadd__, __rmul__ and __add__ in https://github.com/Legrandin/pycryptodome/blob/master/lib/Crypto/PublicKey/_point.pyi; also, the x and y properties return Integer but are typed as -> int https://github.com/Legrandin/pycryptodome/blob/master/lib/Crypto/PublicKey/_point.py#L272.

There are probably other cases where int vs Integer is inconsistent but these are the ones that I ran into.

There also appears to be an issue with the order of operands for scalar multiplication. For variables

h: ECCPoint = ...
x: Integer = ...

x * h  # causes mypy to produce: `error: Unsupported operand types for * ("IntegerBase" and "EccPoint")`
h * x  # mypy OK
assert x * h == h * x  # passes

Happy to make a PR for the ones above if that's OK.