docs: PDE Update

[karl-cardenas-coding]

…limitation

Describe the Change

This PR updates the PDE index page to point to the new tutorial and call out the limitation of PDE and self-hosted Palette.

Review Changes

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[ritawatson]

One typo and a small comment - otherwise, LGTM.

[spectro-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: karl-cardenas-coding, ritawatson
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