Task/395 pagination queries

### Description
Pagination implemented and with rudimentary unit tests.
URI params 'offset' and 'limit' used.
A third URI param 'details' steers whether 'mongo db count' command is issued on no hits.

These hyperlinks (files#discussion_r13659735) don't work in my environment.
Very annoying, but, for now, at least, please use another way to say 'ditto'.

However, this is about the comment for the "Count: XXX" as details, and it was fixed in a2e14c7