Migrate build to Gradle 9 #28

Job	Run time
Build scip-java CLI	4m 18s
gradle-mixed-okio-jmh	2m 47s
gradle-java21-readiness	1m 38s
gradle-kotlin-okio	3m 20s
maven-kotlin-json-kotlin-maven	2m 44s
gradle-kotlin-flowext	8m 44s
maven-java17-spring-boot	2m 36s
bazel-java-examples	7m 58s
	34m 5s

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