Add --static-ip flag

[spowelljr]

A --static-ip flag should be added to minikube start, this flag will only be for Docker and Podman (for now anyway).

This flag will operate somewhat similarly to the --subnet flag.

Currently a CIDR passed to --subnet assigns values as follows:

IP:        CIDR[0]        = 192.168.49.0
Gateway:   CIDR[1]        = 192.168.49.1
MinClient: CIDR[2]        = 192.168.49.2
MaxClient: CIDR[2nd last] = 192.168.49.254
Broadcast: CIDR[last]     = 192.168.49.255

This should be modified so the first IP is MinClient:

MinClient: CIDR[0]        = 192.168.49.0
MaxClient: CIDR[4th last] = 192.168.49.252
IP:        CIDR[3rd last] = 192.168.49.253
Gateway:   CIDR[2nd last] = 192.168.49.254
Broadcast: CIDR[last]     = 192.168.49.255

This will ensure that minikube ip will be the IP the user passed in.

To ensure that we get the desired IPs a mask of /30 should likely be used as that will give us a range of 4 values, this will require that the last digit of the IP is <= 252.

Opposed to the --subnet flag there shouldn't be any incrementing and retrying if the range specified is in use, if it's in use we should fail the start.

Example of desired output if network is free:

$ minikube start --static-ip=192.168.60.0
...
$ minikube ip
192.168.60.0