Add endpoint to produce customizable citation

[helrond]

Is your feature request related to a problem? Please describe.

Citations are currently formatted in DIMES. This makes customizing them difficult, and moves some data customization out of the data layer.

Describe the solution you'd like

Provide an endpoint which returns a citation for a given object or collection, something like: /objects/{objectId}/citation

Describe alternatives you've considered

The other option is to implement additional customization in DIMES, but full flexibility will likely require changes to the data provide to DIMES anyway.