Update backend to Java 17 #455

Job	Run time
PhotonClient Build	42s
PhotonClient Build	42s
Gradle Build	4m 15s
Gradle Build	4m 15s
Build Offline Docs	51s
Build Offline Docs	51s
Build Examples	4m 53s
Build Examples	4m 53s
Photonlib - Build Docker - Athena	6m 48s
Photonlib - Build Docker - Athena	6m 48s
Photonlib - Build Host - Win64	7m 42s
Photonlib - Build Host - Win64	7m 42s
Photonlib - Build Docker - Raspbian	7m 19s
Photonlib - Build Docker - Raspbian	7m 19s
Photonlib - Build Host - macOS	5m 43s
Photonlib - Build Host - macOS	5m 43s
Photonlib - Build Docker - Aarch64	8m 10s
Photonlib - Build Docker - Aarch64	8m 10s
Photonlib - Build Host - Linux	4m 32s
Photonlib - Build Host - Linux	4m 32s
Build fat JAR - Win64	1m 53s
Build fat JAR - Win64	1m 53s
Build fat JAR - macOS	1m 52s
Build fat JAR - macOS	1m 52s
Build fat JAR - Linux	1m 51s
Build fat JAR - Linux	1m 51s
Build fat JAR - macOSArm	1m 56s
Build fat JAR - macOSArm	1m 56s
Build fat JAR - LinuxArm32	1m 13s
Build fat JAR - LinuxArm32	1m 13s
Build fat JAR - LinuxArm64	15s
Build fat JAR - LinuxArm64	1m 22s
Build image - ${{ matrix.image_url }}	0s
Build image - ${{ matrix.image_url }}	0s
release	0s
release	0s
	2h 0m 57s

Provide feedback