Hyper-V: Use the "Default Switch" (NAT based) by default

[tstromberg]

Manually configuring HyperV networks is painful and a cause of many user issues. We should just create the network automatically, as with other VM drivers.

[medyagh]

That should be do-able, Microsoft has instructions to create virtual switch in command line
https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/quick-start/connect-to-network

the only tricky part I see is, deciding which adaptor to connect the switch to ( WIFI, Ethernet, other virtual interfaces)

[tstromberg]

This would address many bugs, such as #3963

@gbraad has mentioned that this may cause breakage when a VM is moved between network adapters.