Add initial Copilot instructions #7067

Job	Run time
Packaging: Config file (macos-latest, linked)	1m 39s
Packaging: Config file (ubuntu-latest, default)	1m 12s
Packaging: Config file (macos-latest, default)	1m 34s
Packaging: Config file (windows-latest, linked)	3m 21s
Packaging: Config file (windows-latest, nightly-latest)	3m 19s
Packaging: Config file (macos-latest, nightly-latest)	1m 19s
Packaging: Config file (ubuntu-latest, nightly-latest)	1m 9s
Packaging: Config file (ubuntu-latest, linked)	1m 7s
Packaging: Config file (windows-latest, default)	3m 31s
	18m 11s

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