Added Dashboards for DHCP

[jelmervdm]

Not something urgently needed, but down the line I would love to see more information / stats regarding the DHCP scopes. Number of leases per scope, Leases in use as a percentage of the scope, maybe some sort of turnover rate, etc.?

I have the grafana dashboard up and running, so I might play around with that some more

[ShreyasZare]

Thanks for asking. There is a major upgrade for DHCP planned with DHCPv6 support and also add multiple features that have been requested. So, will try to get this too with it.