Add nvcaps package for getting MIG minors and NVIDIA device major versions

This change adds a function that reads the mig-minors file to generate a map of MIG capabilit proc path to device major, minor pair (encapsulated in a device) struct. This mirrors functionality in both the device plugin as well as libnvidia-container.

A function that extracts device major numbers for NVIDIA devices from /proc/devices is also provided.

Signed-off-by: Evan Lezar elezar@nvidia.com