WIP: remove kms encryption from TechPreview feature gate

[flavianmissi]

we're reducing the batch size of the kms encryption feature to allow for incremental feature delivery.

[openshift-ci]

Hello @flavianmissi! Some important instructions when contributing to openshift/api:
API design plays an important part in the user experience of OpenShift and as such API PRs are subject to a high level of scrutiny to ensure they follow our best practices. If you haven't already done so, please review the OpenShift API Conventions and ensure that your proposed changes are compliant. Following these conventions will help expedite the api review process for your PR.

[openshift-ci]

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[openshift-ci]

@flavianmissi: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/verify-crd-schema	48b6216	link	true	/test verify-crd-schema
ci/prow/verify-crdify	48b6216	link	true	/test verify-crdify
ci/prow/images	48b6216	link	true	/test images
ci/prow/minor-e2e-upgrade-minor	48b6216	link	true	/test minor-e2e-upgrade-minor
ci/prow/minor-images	48b6216	link	true	/test minor-images
ci/prow/verify	48b6216	link	true	/test verify
ci/prow/okd-scos-e2e-aws-ovn	48b6216	link	false	/test okd-scos-e2e-aws-ovn

Full PR test history. Your PR dashboard.

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