Feature/algorithm integrate and findroot scalar

What this MR does / why does DuMux need it: Add algorithms for integration and root finding for scalar functions

• A 1d Newton root finding method
• A 1d Brent root finding method (https://en.wikipedia.org/wiki/Brent%27s_method)
• A 1d general purpose integration code based on double exponential integration (https://en.wikipedia.org/wiki/Tanh-sinh_quadrature)
• A 2d simplex "quadrature" rule that virtually refines the simplex and each fine cell is an elementary integration volume

Special notes for your reviewer:

• All methods have unit tests added