Scope resources to folder

We use the Folders plugin to organize the jobs on our Jenkins server. https://plugins.jenkins.io/cloudbees-folder/ We would like the ability to manage lockable resources per folder, so that they can be managed by folder admins rather than the global Jenkins admins. When looking up resources or labels, it should do a search up the folder hierarchy, in the same fashion that credential lookups are handled currently.

For ephemeral resources (where no matching resource is found in the hierarchy), I think it would be reasonable for it to continue to create them at the global level by default (to preserve the existing behavior). In the future it could be nice to make this configurable, either with an option in the `lock` step, or a configuration option on the folder itself, but we have no use case for this at this time.