Add new tag mascaret_cas

Since a while (more than 1 year), 2 vnv.py scripts (converting and executing MASCARET file without so much interest: vnv_convert_all_cour_xcas_cas_exe.py and vnv_convert_all_masc_xcas_cas_exe.py) take a long time (2 times 15 min = 30 min at least) to be run on EDF clusters (which total duration is about then 3 h). This is a waste of time for clusters.

The creation of a new tag not to run them on daily validation on EDF clusters is suggested.