Add parset keyword h5parm for gaincal
Created by: revoltek
some inconsistencies between gaincal and ddcal:
- the haparm option in ddecal is parmdb=*h5 in gaincal
- the caltype option in ddecal is called mode in gaincal
- the "caltype" and "mode" names are not called in the same way (e.g. complexgain vs fulljones)