Add ability to create resource group and it's resources in single Bicep file without use of module

This would simplify the very common scenario of creating a resource group, then create resources within it. The resource group is either left out and created via CLI first OR the workaround is to set targetScope to subscription, create resource group resource, then use a module to create the resources within the resource group. For simplicity's sake, I should be able to create all of my infrastructure in a single file.

Start with the CLI-first and subscription targetScope/module workflows described in the issue, then trace how a single Bicep file is parsed and deployed across resource-group and subscription scopes. Done means one file can create the resource group and its resources without requiring a module or a separately created resource group.

Written by the indexing model from the issue text.