Custom state check configuration for TF plugin framework resources

[sergenyalcin]

Description of your changes

We observed that a new region interceptor for the AWS TF Framework Plugin resources was introduced. This interceptor intervenes between API calls and the upjet fw controller and unconditionally injects the region into the state.

In the upjet fw controllers, we rely on the API request will return the uninterpreted state (the original form). If this state does not reflect the actual state, it will affect the decision-making processes of the upjet fw controller.

For example, in the Observe call of the upjet fw controller, we decide whether a resource exists by checking whether the returned state is null. However, as pointed out, the interceptor always injects the region field. So, every null check will return false, which means that this check will not work correctly. Also, the TF plugin framework's internal decisions rely on performing checks based on whether the state is null or not.

To handle this problem, we introduced a new configuration mechanism for framework resources. At this resource level, it will provide a generic structure for resolving this issue. The goal is to write custom state checks based on specific conditions at the provider and resource levels to determine whether the state is truly empty.

The main reasons for implementing this generically are to avoid moving provider—and resource-specific logic to upjet, to enable the creation of custom empty checkers at the resource level capable of handling the effects of different interceptors in specific situations, and to keep the scope of this change provider—and resource-specific.

I have:

• Read and followed Upjet's contribution process.
• Run make reviewable to ensure this PR is ready for review.
• Added backport release-x.y labels to auto-backport this PR if necessary.

How has this code been tested

Tested locally for a few TF plugin framework resources.

[erhancagirici]

Thanks @sergenyalcin , overall looks good to me. I left a nit comment, which is not a blocker.