get rid of ./lib/* fork

This somehow depends on #588 but can be done w/o that finished as well. Code under ./lib is basically a fork of an old project that now fully lives in openshift/library-go.

We need to:

• Fix #588 (but again, this issue can be done 99% w/o that)
• Move existing code to use openshift/library-go/pkg/operator/resource/* for core types
• drop ./lib

As of today, since #588 isn't done yet, we can work on the second point above as follows:

• Move existing code to use openshift/library-go/pkg/operator/resource/* for core types (instead of our ./lib/resource* packages)
• leave under ./lib just ./lib/*/machineconfig* files, types and funcs since we still need those till #588 is done
• while removing funcs from the above, contribute any core func to library-go as well (if any, haven't checked).

Example:

Move https://github.com/openshift/machine-config-operator/blob/fcf5aa07db58710cb22093deb1ef2dad320bf3eb/pkg/operator/sync.go#L80 to https://github.com/openshift/library-go/blob/master/pkg/operator/resource/resourceapply/apiextensions.go#L32 (applies for resourceread package and the others as well in the surrounding lines)

Start by comparing pkg/operator/sync.go and the surrounding ./lib/resource* packages with the corresponding openshift/library-go/pkg/operator/resource/* packages, including resourceread and resourceapply. The work is done when core code uses library-go, ./lib retains only the machineconfig files, types, and functions needed until #588, and any remaining core functions are contributed to library-go.