Improve behavior when deleting a Katello environment
With the current Katello engine, when a Katello environment is deleted, the related Foreman environments (i.e. puppet environments) are also deleted.
The issue with this behavior is that if a puppet environment has a host associated with it, the deletion will fail.
This issue was raised while working on the following: https://github.com/Katello/katello/pull/3576#discussion-diff-8996233L257, which integrates logic from the existing foreman-katello-engine & katello-foreman-engine in to the core katello engine.
The proposed solution is to not allow katello lifecycle environment to be deleted, if one or more of the foreman puppet environments cannot be deleted.