Support vmnet networking without elevated permissions
Additional information:
Here is a command, that doesn't work when running as normal user:
```bash
$ qemu-system-aarch64 \
    -device virtio-net-pci,netdev=net0 \
    -netdev vmnet-bridged,id=net0,ifname=en0 \
    -machine virt
```
It fails with:
```
qemu-system-aarch64: -netdev vmnet-bridged,id=net0,ifname=en0: cannot create vmnet interface: general failure (possibly not enough privileges)
```

When running the same command using elevated permissions (i.e. via `sudo`), it works without any issue.