Problem statement from Davis Wahl:
In brief, we need to be able to quickly associate entitlements with consumers, so that we can sort and group consumers by the entitlements they consume. 

While the consumer/entitlement endpoint does this, it can only target a single consumer, which means making 1 rest call per consumer -- which is prohibitively slow for non trivial #'s of consumers. 


From an email thread between Davis and Vritant:
Add an owner_id query parameter, so we can at least restrict the
total data in the set to match against to just the entitlements owned
by the owner

This exists in Candlepin 2.0, but we are requesting it be backported to 0.9.51 to unblock current work on RHN UI EOL stories.

Version-Release number of selected component (if applicable): 0.9.51