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).