Create 14.7 What's New entry

What does this MR do and why?

Describe in detail what your merge request does and why.

Creates the What's New entry for the 14.7 release. IMPORTANT: This should not be merged until after the release post has gone live on the 22nd.

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How to set up and validate locally

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MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.