DRILL-6019: Only admin should be able to access shutdown resources and information about process and admin users
1. Only admin should be able to access shutdown resources via REST API.
2. Modified ClusterInfo to show information about process and admin users only when user is logged in and is admin.
3. Added drillbits comparison based on thier adress and ports to check if drillbits are the same (DRILL-6006)
closes #1065
