Add license reporting and "vcpkg license-report" command. #1698

Job	Run time
format	2m 36s
json-schema	58s
builds / build (windows-2022, windows-ci)	19m 21s
builds / build (ubuntu-20.04, linux-ci)	9m 32s
builds / build (macos-12, macos-ci)	17m 23s
	49m 50s

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