refactor data_app_group to use plugin-framework

[exitcode0]

I've not yet tested this code

Also not sure if the test cases will need to be re-written for terraform-plugin-framework

[monde]

Thanks @exitcode0
Is there a bug here? I'm trying to harden up the reliability of the Okta TF releases and I don't want to take up code changes in behavior implementation unless they are are fixing a bug.

[exitcode0]

Hey @monde,

No bug here, this is just a general refactor
My understanding is that we'd want to move to plugin-framework for a v5?
If we action #2208 I think it makes more sense for this PR target that branch instead of master