This patch updates the way the CRD generator compares an imported
metav1 package. Previously the comparison occurred using a Golang
equality operator, !=, against two, in-memory data structures.
However, this fails when multiple root paths are loaded. Their
metav1 packages are identical, just not identical objects in
memory. This patch updates the comparison to compare the package
IDs, not the instance of the object.

This patch also introduces a filesystem-path specific loader for
each unique filesystem path provided as a root. This ensures the
AST is loaded correctly and the kubebuilder markers are parsed as
intended.

This patch adds tests to reproduce the issue of the markers
not being discovered when multiple paths are used.

The issue is not markers missing from a type, but markers missing
from a *referenced* type. For example, the new Job type imports
the unserved.CronJobSpec as the field Job.Spec.CronJob. The
markers are not generated for Job.Spec.CronJob as it is referenced
from another package.