Introduce docc documentation and "supported features" #768

Job	Run time
Documentation check (6.1.2, jammy, corretto)	21s
Test (Java) (jammy swift:6.1.2 jdk:corretto)	2m 7s
Test (Java) (macos swift:6.1.2 jdk:corretto)	1m 9s
Benchmark (JMH) (jammy swift:6.1.2 jdk:corretto)	2m 7s
Test (Swift) (jammy swift:6.1.2 jdk:corretto)	2m 7s
Test (Swift) (macos swift:6.1.2 jdk:corretto)	1m 9s
Sample JavaProbablyPrime (jammy swift:6.1.2 jdk:corretto)	2m 7s
Sample JavaDependencySampleApp (jammy swift:6.1.2 jdk:corretto)	2m 7s
Sample SwiftKitSampleApp (jammy swift:6.1.2 jdk:corretto)	2m 7s
Sample SwiftAndJavaJarSampleLib (jammy swift:6.1.2 jdk:corretto)	2m 7s
Sample JavaSieve (jammy swift:6.1.2 jdk:corretto)	46s
Sample JExtractJNISampleApp (jammy swift:6.1.2 jdk:corretto)	2m 8s
Sample JavaProbablyPrime (macos swift:6.1.2 jdk:corretto)	1s
Sample JavaDependencySampleApp (macos swift:6.1.2 jdk:corretto)	1s
Sample JavaSieve (macos swift:6.1.2 jdk:corretto)	1s
Sample JavaKitSampleApp (macos swift:6.1.2 jdk:corretto)	1s
Sample JavaKitSampleApp (jammy swift:6.1.2 jdk:corretto)	2m 8s
Sample SwiftKitSampleApp (macos swift:6.1.2 jdk:corretto)	1s
Sample JExtractJNISampleApp (macos swift:6.1.2 jdk:corretto)	1s
Sample SwiftAndJavaJarSampleLib (macos swift:6.1.2 jdk:corretto)	9s
soundness / License headers check	6s
soundness / Broken symlinks check	5s
soundness / Documentation check	0s
soundness / Shell check	32s
soundness / API breakage check	0s
soundness / Format check	0s
soundness / YAML lint check	5s
soundness / Unacceptable language check	4s
soundness / Python lint check	8s
	23m 45s

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