Description of problem:
The HTML output format is returning the object itself not the value of the object for Host Collections and Products in Entitlement report.
Subscriptions column in Registered hosts report is also affected.

Steps to Reproduce:
1. Go to monitor -> Report Templates -> Entitlements -> Generate
2. Select the Output format of HTML
3. Click submit and download the report

Actual results:
Host Collections:
#<Katello::HostCollection::ActiveRecord_Associations_CollectionProxy:0x0000000021043cd0>

Expected results: The value of the object.

Additional info: This occurs through the UI, CLI, and API.