Provide a list of "waiting" job for lockable resources in the order they will be treated

[ykoehler]

It would be desirable to see which job is next for the locks once it gets released.

Likely in the page where the lockable are displayed:

https://jenkins-ion.arubanetworks.com/lockable-resources/

We can today see that a lock is used or not, but adding a "list of pending lock requests" would help the user understand their job is likely to get the lock.