* Add support for scoped resources
* refactor existing checks addrs and add check block addr
* Add configuration for check blocks
* introduce check blocks into the terraform node and transform graph
* address comments
* address comments
* don't execute checks during destroy operations
* don't even include check nodes for destroy operations
Previously we were attempting to infer the checkable object address kind
of a given address by whether it included "output" in the position where
a resource type name would otherwise go.
That was already potentially risky because we've historically not
prevented a resource type named "output", and it's also a
forward-compatibility hazard in case we introduce additional object kinds
with entirely-new addressing schemes in future.
Given that, we'll instead always be explicit about what kind of address
we're storing in a wire or file format, so that we can make sure to always
use the intended parser when reading an address back into memory, or
return an error if we encounter a kind we're not familiar with.
This is a new-shaped representation of check results which follows the
two-tiered structure of static objects and dynamic instances of objects,
thereby allowing consumers to see which checkable objects exist in the
configuration even if a dynamic evaluation error prevented actually
expanding them all to determine their declared instances.
Eventually we'll include this in the state too, but this initially adds it
only to the plan in order to replace the now-deprecated experimental
conditions result that was present but undocumented in Terraform v1.2.
