Document how to enable container tunnel #5515
Description
Describe the issue or suggestion
Aspire 13 introduces a new experimental feature: container tunnel https://github.com/dotnet/aspire/blob/davidfowl/whats-new/tools/ReleaseNotes/data/whats-new-13.md#universal-container-to-host-communication We should document what it provides and how to enable it.