Adds the ability to target resources within modules, like:
module.mymod.aws_instance.foo
And the ability to target all resources inside a module, like:
module.mymod
Closes#1434
Only used in targets for now. The plan is to use this for interpolation
as well.
This allows us to target:
* individual resources expanded by `count` using bracket / index notation.
* deposed / tainted resources with an `InstanceType` field after name
Docs to follow.