Custom hiera backends configured at the project layer should be allowed to return values bound to any key.

[PaulGale]

(written with the assistance of Henrik Lindberg)

Describe the Bug

As a user of Bolt having hiera backends that return values that should be bound to global keys (in my case environment variables) it is not possible to use such a backend at the project layer since it behaves as a puppet module. The observed behavior is that it actually works while giving a warning that the returned hash from the backend “must use keys qualified with the name of the module” (this is a separate issue, it should actually prune those keys as stated in the documentation - logged https://tickets.puppetlabs.com/browse/PUP-11719 for that).

Expected Behavior

The expected behavior is that backends configured at the project layer should be allowed to return values bound to any key. Without this it becomes difficult to reuse these kinds of backends for puppet with bolt as they would need to be able to prefix all keys with the name of the project.