Add per-guide star bitMask in pfsDesign

Quoting RHL :

We need new flags in the pfsDesign files which indicate which stars are acquisition stars (i.e. with proper motion/parallax), which objects are present in the field and can be used for identifying the field but should not be used to find the initial dx/dy/drotation/dscale, which stars can be used for guiding after their centroids have been measured relative to good GAIA stars, and which objects should not be used to guide (e.g. galaxies).   Those flags need to be used by the AGCActor and passed to the OPDB/FGW (I take it that's Eric's set of windows

From what I understand from that comment, we could need 4 different bits:

• Bit 0 (0x01) → Acquisition Star (Has proper motion/parallax, used for initial acquisition)
• Bit 1 (0x02) → Field Identification Star (Used for identification but not for computing dx/dy/drotation/dscale)
• Bit 2 (0x04) → Guiding Star (Relative Centroiding) (Can guide only after being referenced to good GAIA stars)
• Bit 3 (0x08) → Non-Guiding Object (Should not be used for guiding, e.g., galaxies)