Engine: rabl: add Katello namespacing to Util::Data references

Without this change, errors like the following may be observed
when attempting to access the rabl:

...
With body: {"displayMessage":"uninitialized constant Util","errors":["uninitialized constant Util"]}
Engine: add anemone to katello.rb

Adding anemone to katello.rb.  This gem is needed to support
repo discovery.  Without it, you might observe an error
like the following in the delayed jobs log:

... uninitialized constant Katello::RepoDiscovery::Anemone
Merge pull request #3493 from bbuckingham/fix-rabl-namespacing

Engine: fixes for repo descovery and other rabl files