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.

Nope,
according to the google lint script, assuring the style guide is followed, if a parameter is to be modified, the c++ reference is not to be used, but normal C pointers.