[Docs] Add docs for how folks can use azd to access vnets

When deploying services within a vnet, users have some alternatives for how to get access and either deploy services or just debug their service.
For example, they can create a VPN Gateway or use a VM+bastion.

To resolve this issue, generate docs about how to use azd to help with this connection; for creating the connection and deleting it when it is not needed anymore.