Revert changes that added RIT resource + datasource

[modular-magician]

This resource was added at both beta and GA but appears to only work at beta. While I'd fix-forward normally this is a handwritten resource and we're cutting the next release EOD tomorrow. This ensures that we don't end up mixing up branches and releasing the resource without a working GA API- a roll-forward will need to explicitly target beta only, or confirm that the GA API works as expected.

Upstream version of the changes to release branches in hashicorp/terraform-provider-google#14183 and #5416

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• Searched through the issue tracker for an open issue that this either resolves or contributes to, commented on it to claim it, and written "fixes {url}" or "part of {url}" in this PR description. If there were no relevant open issues, I opened one and commented that I would like to work on it (not necessary for very small changes).
• Ensured that all new fields I added that can be set by a user appear in at least one example (for generated resources) or third_party test (for handwritten resources or update tests).
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Derived from GoogleCloudPlatform/magic-modules#7608