Add kldinfo(8), a simple utility to view module dependencies and their version

[rz_fabmicro.ru]

Summary

kldinfo utility parses ELF header of a given KLD module file, then searches for
available Kernel Loadable objects and shows their dependency and version
information. If path to file is given the utility tries to open it directly.
It quits if open fails. Otherwise, it searches for .ko in directories set by
kern.module_path sysctl variable. Can be used to show builtin modules in kernel.

[rz_fabmicro.ru]

Dupe. Please proceed to: https://reviews.freebsd.org/D60634