Move the `/pkg/pf/README.md` user facing docs into `/docs` #5769

Job	Run time
Ensure test assets build cleanly	55s
Test and Lint / lint	2m 30s
Test and Lint / test (1.22.x, ubuntu-latest, DEFAULT)	54m 21s
Test and Lint / test (1.22.x, ubuntu-latest, PULUMI_TF_BRIDGE_ACCURATE_BRIDGE_PREVIEW)	55m 34s
Test and Lint / test (1.22.x, macos-latest, DEFAULT)	5m 36s
Test and Lint / test (1.22.x, macos-latest, PULUMI_TF_BRIDGE_ACCURATE_BRIDGE_PREVIEW)	4m 47s
Test and Lint / test (1.22.x, windows-latest, DEFAULT)	15m 43s
Test and Lint / test (1.22.x, windows-latest, PULUMI_TF_BRIDGE_ACCURATE_BRIDGE_PREVIEW)	13m 39s
Test and Lint / test (1.23.x, ubuntu-latest, DEFAULT)	54m 12s
Test and Lint / test (1.23.x, ubuntu-latest, PULUMI_TF_BRIDGE_ACCURATE_BRIDGE_PREVIEW)	54m 12s
Test and Lint / test (1.23.x, macos-latest, DEFAULT)	5m 55s
Test and Lint / test (1.23.x, macos-latest, PULUMI_TF_BRIDGE_ACCURATE_BRIDGE_PREVIEW)	4m 25s
Test and Lint / test (1.23.x, windows-latest, DEFAULT)	19m 15s
Test and Lint / test (1.23.x, windows-latest, PULUMI_TF_BRIDGE_ACCURATE_BRIDGE_PREVIEW)	14m 48s
	5h 5m 52s

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