Move docs in-source #1378

Job	Run time
PhotonClient Build	37s
Gradle Build	3m 18s
Build Examples	4m 18s
Build Offline Docs	39s
Photonlib - Build Docker - Athena	4m 52s
Photonlib - Build Host - Win64	7m 54s
Photonlib - Build Docker - Raspbian	5m 11s
Photonlib - Build Docker - Aarch64	5m 37s
Photonlib - Build Host - macOS	3m 58s
Photonlib - Build Host - Linux	3m 58s
Build fat JAR - Win64	2m 6s
Build fat JAR - macOS	3m 23s
Build fat JAR - macOSArm	3m 36s
Build fat JAR - Linux	1m 15s
Build fat JAR - LinuxArm64	1m 11s
smoketest-RaspberryPi	59s
run-smoketest-native (ubuntu-latest, jar-Linux, -Djdk.lang.Process.launchMechanism=vfork)	13s
run-smoketest-native (windows-latest, jar-Win64)	18s
Build image - ${{ matrix.image_url }}	0s
run-smoketest-native (macos-latest, jar-macOS, x64)	14s
release	0s
Combine	17s
	53m 54s

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