Add more information nmcli shows about route

Nmcli shows destination and prefix information about route but not next hop and metric. Both of those are accesible with more detailed command (such as nmcli connection show ) but it would be easier to have them available more easily.

So I created function that prints available information about route (destination, prefix and then next hop and metric if they exists) and prints them into buffer.

This buffer is then printed when nmcli command is triggered, resulting in at least same output as before this merge request, while possibly displaying next hop and metric as well.