Return content_guard PRN from distribution

[ianballou]

Is your feature request related to a problem? Please describe.
In Katello, we save content guard hrefs from data returned from the distribution API. To switch to using only PRNs - we'd ideally be able to get the PRN from the same source.

Describe the solution you'd like
Have a new content_guard_prn data point returned with distributions.

Describe alternatives you've considered
Otherwise we can look up the content guard and save the PRN.

[ggainey]

One clarification here - you can't retrieve an entity using just the PRN. PRNs are useful for things like prn__in in list-calls, for example - but to do a GET on the entity itself, we still require HREFs, because you need the routing to know what you're asking for and what you're getting back.

[ianballou]

One clarification here - you can't retrieve an entity using just the PRN. PRNs are useful for things like prn__in in list-calls, for example - but to do a GET on the entity itself, we still require HREFs, because you need the routing to know what you're asking for and what you're getting back.

This issue was from a time when we thought hrefs would no longer be stored as references to other objects in Pulp 4.
But, it would be nice to be able to store the content guard PRN from a distribution without having to look up the content guard via the API and then retrieve the PRN. That way we could get the content guard PRN in one API call instead of two.