Search results should support pagination

[FruitieX]

Given a page token, the backends should be able to provide search results starting from a certain page. Implementations may vary, some backend services may provide us with a huge list with each query (this should then perhaps be cached), and other services may already have a concept of pages with tokens which we could then use directly. Core implementation should be generic enough to handle both of these cases, and let the backend modules decide the details of implementation.