add dedicated IIC commands for SuNSS

We'll a limited set of IIC command for SuNSS:
basically :

iic startSuNSSAcquisition exptime=...

In other words, take a scienceObject on the SM fed by SuNSS.

iic finishSuNSSAcquisition

Close the shutter(s) right away, create the file(ccd read) and return.

iic abortSuNSSAcquisition

Close the shutter(s) right away, trash the file and return.