Dynamic Data should be accesible by the search route as well

Description

Dynamic data (such as availability of books or ticket numbers) had seperated routes on the backend which were create by backend plugins. In the future thise SCThing should be accesible by the search as well.

This could be done by either mixing in the data with the data from the database or extending the query so the app can decide which kind of data it wants to see...

cc: @krlwlfrt