📖 docs: add storage backends, and remaining contents in overview

[RayyanSeliya]

Summary

Adds the remaining sections to the KubeFlex overview documentation including Storage and Backends, PostCreateHooks, Use Cases, Quick Start, and Next Steps. This completes the overview documentation with comprehensive coverage of KubeFlex's capabilities, automation features, practical use cases, and navigation to additional resources.

Related issue(s)

Part of the documentation restructuring for kflex.dev docsite development.

[kubestellar-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[kubestellar-prow]

Hi @RayyanSeliya. Thanks for your PR.

I'm waiting for a kubestellar member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[clubanderson]

⚠️ Unit test failing due to stale base branch

This PR targets the doc-kubeflex branch which hasn't been updated since October 2025. Please merge main into doc-kubeflex or rebase onto main.

[clubanderson]

/ok-to-test

[kubestellar-prow]

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

Test name	Commit	Details	Required	Rerun command
pull-kubestellar-kubeflex-test-unit	e95fbee	link	true	/test pull-kubestellar-kubeflex-test-unit

Full PR test history

Details

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository. I understand the commands that are listed here.