Add signpost text to the bridge network settings that explicitly notes this should be an isolated L2 broadcast domain

[zjs]

Additionally, we could say that it should be a VXLAN or should be configured with a VLAN ID.

[zjs]

This is a very low priority, but could be included in the release if it is a simple text change that can be made without sacrificing something else.

[lweitzman]

I suggest: "Bridge networks are the network or networks that container VMs use to communicate with each other. Every virtual container host (VCH) must have a unique bridge network. Do not use the bridge network for any other VM workloads, or as a bridge for more than one VCH."
@pdaigle @hickeng @zjs

[stuclem]

@cristianfalcone, the proposed text from @lweitzman looks good to me.