Add to the CLI fuel command the possibility to filter by roles and list only IPs

Many times we have to run shell loops to modify clusters on the fly.
Please add to the fuel/fuel2 CLI tool, commands to get the nodes IPs filtered by role, like

`fuel nodes --controllers -q`
10.170.40.10
10.170.40.11
10.170.40.12

Or `fuel nodes --computes -q`
10.170.40.20
10.170.40.21
10.170.40.22
10.170.40.23
10.170.40.24
10.170.40.24

You say that with egrep and awk it's easy.
But when customers rename nodes adding spaces, that might be a problem.
Imagine a complex for loop working there and creating unmanageable chaos just because of syntax.