Use the label parser from build agent selection in the lockable-resources plugin

Hi community

I want to fix this issue in lockable-resources plugin.

I tries to check how it is done in node() step but I am lost. I have no idea, how are the label parsed and how to get list of all matched resources.

Any idea will be helpful. This one enhancement might helps many users and close many of open items and PRs in the plugin. So when somebody want to contribute are welcome :wink: