## Support multiple clientid and username Query string parameters in "/clients" API

Multi clientid/username queries examples:
 - "/clients?clientid=client1&clientid=client2
 - "/clients?username=user11&username=user2"
 - "/clients?clientid=client1&clientid=client2&username=user1&username=user2"

## Add an option to specify which client info fields must be included in the response

Request response fields examples:
 - "/clients?fields=all" (omitting "fields" Qs parameter defaults to returning all fields)
 - "/clients?fields=clientid,username"