[pmkfskff] Quadratic Binary Diophantine

Quadratic Diophantine equations in two variables seem to be algorithmically solvable usually if not always, though the algorithms seem hairy.

Challenges for correct, elegant, or fast implementations.

A little bit of a challenge in describing the output: a solution could be an infinite set.

The famous quadratic Diophantine equation in 2 variables is the Pell equation.

https://www.alpertron.com.ar/METHODS.HTM describes some solution methods.

Inspired by the incomplete "diophantine" package on hackage.