Clarify "Shared network"

**Describe the issue**

According to [network-mode](https://docs.getutm.app/settings-apple/devices/network/#network-mode):

> Traffic is routed directly by the host operating system and the guest shares a VLAN with the host. Services running on the guest and the host can see each other without additional configuration. This is recommended for new virtual machines.

The docs do no not mention access between VMs, but the term *Shared Network* is a hint that this should work.

I'm trying to access one VM from another VM, using Apple virtualization in both, and it looks like there this works only with Bridged network. Is this expected?

When both vms are using *Shared network*, I can access the VM from the host, or the host from the VM, but I cannot access to another VM (tested with iperf3).

When both VMs are using *Bridged* network, I have have network access between the VMs.

Is shared network using [VZNATNetworkDeviceAttachment](https://developer.apple.com/documentation/virtualization/vznatnetworkdeviceattachment?language=objc) and bridged network using [VZBridgedNetworkDeviceAttachment](https://developer.apple.com/documentation/virtualization/vzbridgednetworkdeviceattachment?language=objc)? In this case it is clear why this does not work.

This looks like a documentation issue, the docs should help users that need access between VMs to choose the right network mode.

Also the Network page for a VM could have a simple description of each mode, or a link to the section in the docs for each type. The only thing we have is "Shared Network" and "Bridged (advanced)". These names do not help users that do not know the way networking is implemented in UTM.

**Configuration**
* UTM Version: Version 4.5.3 (99)
* macOS Version: 14.6.1
* Mac Chip (Intel, M1, ...): M1 Pro