Add C `Contracts` package #2735

Job	Run time
Prepare supported CodeQL environment matrix	5s
Run Guideline Recategorization tests	8s
Run release tests	11s
Run analysis report tests (2.18.4, codeql-cli/v2.18.4, codeql-bundle-v2.18.4)	3m 55s
	4m 19s

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