Option URIs in the JSON API

[Zack-83]

Rationale / Begründung

Similarly to #506, it would be helpful to add URIs at all locations where a RDMO object references another one.

Examples:

/api/v1/options/optionsets/ --> URIs for options, conditions, questions
/api/v1/options/options/ --> URIs for optionsets, conditions
/api/v1/domain/attributes/ --> URIs for parent attributes
/api/v1/conditions/conditions/ --> URIs for pages, questionsets, questions, tasks, target_options
/api/v1/questions/catalogs/ --> URIs for sections
/api/v1/questions/sections/ --> URIs for catalogs, pages
/api/v1/questions/pages/ --> URIs for sections, questionsets, questions
/api/v1/questions/questionsets/--> URIs for pages, parents, questionsets, questions
/api/v1/questions/questions/ --> URIs for pages, questionsets

Affected

Who is affected by the change: Managers, Admins, creators of plugins (for troubleshooting)

[jochenklar]

This is a bit trickier, we need to discuss this. The arrays, e.g. options and questions are used by the interface and there could be a performance issue if we collect the URI for each request. Maybe we need an additional query parameter.