knowledge: fix get_kbs_info query result

* Fixes the right query executed in function.

Signed-off-by: Leonardo Rossi <leonardo.r@cern.ch>
deposit: errorlist typo fix

Signed-off-by: Javier Martin Montull <javier.martin.montull@cern.ch>
restful: addition of `validate` function in RestfulPagination

* Adds a `validate` function in RestfulPagination class that checks
  the ranges of `page` and `per_page` parameters.

Signed-off-by: Konstantinos Kostis <konstantinos.kostis@cern.ch>