make IIC arc/flat compatible with dcb/pfilamps

We currently have working IIC commands which takes arc/flat using dcb/dcb2 .
The scheme is that IIC sends the configuration to the "lightSource" actor and sps deals with the lamp timing eg : _ iic expose arc argon=15 _boils down to:

• dcb prepare argon=15
• sps expose exptime=15 doLamps

In the end, it's only a matter of pointing on the right illumination system and we have the lightSource keyword for that.