BUG: add switch for nu:DphitEff in kEpsilonPhitF (fixes #1560)
Including `nu` in `DphitEff` even though it is not present in (LUU:Eq. 17) provided higher level of resemblance to benchmarks for the tests considered, particularly for the peak skin friction (yet, pressure-related predictions were unaffected). Users can switch off `nu` in `DphitEff` by using `includeNu` entry in `kEpsilonPhitFCoeffs` in order to follow the reference paper thereat. `includeNu` is left `true` by default. See GitLab issue #1560, LUU: Laurence, D. R., Uribe, J. C., & Utyuzhnikov, S. V. (2005).