Implement the Newton (for finding roots) method for solving KLLS

[mertkipcak]

Implements the algorithm for KLLS that uses NonlinearSolve.jl by finding the root of the dual gradient,

$$ A\left(x(y)\right) + \lambda C y - b $$

By running Newton's method for finding roots. Replicates the behaviour of this algorithm

Testing

Tested by a new test in runtests.jl called Newton LS