Merge branch '29-prevent-from-using-specific-sea-ice-boundary-conditions-in-zdftke-and-zdfgls-if-nn_ice-0-i-e-no' into 'main'

Resolve "Prevent from using specific sea ice boundary conditions in zdftke and zdfgls if nn_ice=0 (i.e. no ice model but key_si3 || key_cice)"

Closes #29

See merge request !54

(cherry picked from commit 1d65bcb9)

bc83a255  Changed def. opt. for roughness to "no ice" case