[CONTP-695] add csi driver documentation

[adel121]

What does this PR do? What is the motivation?

Add documentation for CSI driver

Merge instructions

NOT READY FOR MERGE

Merge readiness:

• [ ] Ready for merge

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Additional notes

This PR will remain in draft mode until the final version of the documentation is ready.

[github-actions[bot]]

Preview links (active after the build_preview check completes)

New or renamed files

• https://docs-staging.datadoghq.com/adelhajhassan/add_csi_driver_documentation/containers/csi_driver/

Modified Files

• https://docs-staging.datadoghq.com/adelhajhassan/add_csi_driver_documentation/containers/cluster_agent/admission_controller
• https://docs-staging.datadoghq.com/adelhajhassan/add_csi_driver_documentation/containers/kubernetes/

[github-actions[bot]]

✅ Documentation Team Review

The documentation team has approved this pull request. Thank you for your contribution!

[iadjivon]

Added a card for Editorial review: DOCS-11506

[cswatt]

I pushed changes to standardize capitalization, correct grammar, and other style-related concerns. No content has been substantively changed.

Let me know when this should be merged.