Index fibers from multiple spectrographs in PfsDesign

Our current PfsDesign (and PfsConfig) assumes a single identifier is sufficient to index all fibers in the entire instrument (all spectrographs), which identifier is called fiberId. However, it appears that this is not a scheme that is currently supported/approved in the slit design.

I argue that all fibers should appear in the PfsDesign, so that the 2D pipeline knows what to extract and record; this means that JEG's "science fiber" index (sfib in the "Grand Fiber Map" table) is not sufficient for this.

I believe our options are:
1. Add a spectrograph index to PfsDesign, so the primary keys are the spectrograph and the fiberId; here, fiberId is what JEG calls hole and the slit design calls "Slit position". I think the pipeline can work with this, but may need a bit of tweaking.
2. Extend fiberId so that it incorporates the spectrograph: fiberId= 651*spectrograph + slitPosition. Then fiberId=1..651 are on spectrograph=1, fiberId=652..1302 are on spectrograph=2, and so on. This is my preferred option, as I think the pipeline already supports it.
3. Use both schemes, so the PfsDesign includes spectrograph, hole and fiberId. This might be the most user-friendly, but I worry about the unnecessary duplication of information.