We've had questions a few times about whether it's possible to implement
organization-specific checks that are not appropriate for inclusion in
the clusterlint codebase. For example, a company may have some highly
specific best practice that isn't relevant anywhere else, but want to
enforce it using clusterlint alongside all their other best practices.
Implement this capability by allowing Go plugins to be loaded into
clusterlint at runtime. Document how to build plugins, and provide an
example.