Add pagination to ProjectIrodsFileListAPIView

[mikkonie]

I left this out of #1994, as it requires a bit further effort and I have more critical things on my TODO list.

This view doesn't contain a queryset nor a serializer. It would be rather trivial to implement a generic paginator such as in this example. Alas, IrodsAPI.get_objects() doesn't currently provide functionality to limit the start of search results. Hence, we would need to query for the entire data set for every result regardless of pagination. Hence the spec below.

Spec

• Add optional offset to IrodsAPI.get_objects()
• Add generic list pagination to ProjectIrodsFileListAPIView
• Update samplesheets API version to v1.1, only enable this for v1.1
• Add tests
• Update API documentation

Tagging this for v1.1 for now.