Update SiNumerology for ITkPixel
This merge-request updates the SiNumerology to deal with the more complex ITk pixel geometry in the endcaps. The existing SiNumerology is designed for endcap subsystems with a single layer of multiple disks with multiple rings per disk. The ITk pixel endcaps are instead made of multiple layers of multiple disks with "a single ring per disk". While the existing structure could be somehow "misused" with ITk pixel, since it can also be described with a 2D structure, the names of the methods would be misleading and a dedicated treatment would in any case be needed for the building of the TrackingGeometry which assumes that rings from a given disk share the same z and cover some radial extension.