fixes #5974 / BZ1098165 - content host - fix issue with spinner on package deletion

Prior to this commit when a user would click the (X) to delete
a package, the the (X) would turn in to a spinner and spin forever.
Although, this occured, the package would actually be deleted from
the client (content host).

This commit contains a few changes:
1. Update the behavior of deleting a package to be consistent with
   the other supported actions.  This basically means to take the
   user to the dynflow tasks pane which shows the status/progress
   of the deletion.
2. Remove the existing 'ContentHostTask' logic.  Since the content
   host actions are all dynflow, this logic is no longer used/needed.
3. Update the humanized input of the task to handle the fact that
   when a package is deleted using the list it isn't deleted based
   upon only the package name, but by a hash consisting of
   name+version+release+arch.
@waldenraines, Good catch!  Modeled this one off of the existing actions and it appears that they didn't have an error handler, so I added one based on how we handle it in similar situations.  So now, we'll display the errors if/when they occur on the initial request.