Add C `Contracts` package #2720

Job	Run time
Prepare supported CodeQL environment matrix	8s
Run Guideline Recategorization tests	11s
Run release tests	9s
Run analysis report tests (2.18.4, codeql-cli/v2.18.4, codeql-bundle-v2.18.4)	4m 4s
	4m 32s

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