Implement `NSum` and improve `NIntegrate` with mike-gimelfarb/numerical-integration library

[axkr]

Use this library to implement NSum and improve NIntegrate

• https://github.com/mike-gimelfarb/numerical-integration

@mike-gimelfarb
I did an initial implementation of your project in package org.matheclipse.core.numerics and used the TanhSinh quadrature to implement Method->DoubleExponential.