[freeflow][non-isothermal] Revise non-isthermal model
* rename folder staggeredni -> nonisothermal * use Dune ifelse for energy-transport/storage in fluxVars/localRes * remove now obsolete headers * now independent of discretization
File moved
* rename folder staggeredni -> nonisothermal * use Dune ifelse for energy-transport/storage in fluxVars/localRes * remove now obsolete headers * now independent of discretization