Configure shared networking IP address

**Describe the issue**
When using `shared` networking mode with macOS (12) and ubuntu (20.04), the IPv4 address that the VM gets on my mac is 192.168.64.2.
However, for some use-cases, I need the address to be something else and something pre-defined (for example when using the VM as a development server and some other service has the IP in its configuration).

How could it be possible to define or change the assigned IP to something else? I've tried many options in the advanced settings of the Network tab, but most are not accepted with the shared mode, and none seem to have an effect on the IP address the guest gets.

I've also tried manipulating vmnet from macOS with `ifconfig` (ipconfig set bridge bridgeX...), but I could only change the IP of the bridge and not the VM.

nb: I cannot use the bridged mode with another DHCP server because I don't have control over it.

**Configuration**
* UTM Version: 2.4.0
* OS Version: macOS 12.0.1
* Apple Silicon