Add pagination support for MongoDB

Paginate db query result of MongoDB.
The query methods support pagination include
get_resources, get_meters, get_alarms.
It is a part of blueprint paginate-db-search.

Implements blueprint paginate-db-search

Change-Id: Id9162782a6c96b4bb0ed04d828791b8b1b1379d4
Merge "Add pagination support for MongoDB"