Upgrade Java version to 21 across all build environments

[gchatelet]

Todo list to migrate to JDK 21

• ci: bump workflow
• bazel: bump bazelrc
• ci: bump bazel docker
• cmake: bump cmake/java.cmake
• ci: bump cmake docker
• java: bump ortools/java/*pom.xml.in
• release: bump tools/release dockerfiles
• release: bump tools/docker
• release: update release machines
  • internal: bump internal machine setup documentation

[Mizux]

few notes:

1. moving to openjdk21 in docker may not work as expected (sometime bazel doesn't catch it etc..)
   -> you may need 609b5db
   since docker job are only trigger on push -> need to monitor once merge and apply this fix if needed

2. in java we set the jdk release in the pom.xml
   

   or-tools/ortools/java/pom-local.xml.in

   Lines 51 to 55 in af5487d

   	<properties>
   	<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
   	<maven.compiler.source>1.8</maven.compiler.source>
   	<maven.compiler.target>1.8</maven.compiler.target>
   	</properties>

   
   maybe it's time to set it to 21 too or at least 11
   note: Actually java team failed the version support, and you need a third option on the cli --release IIRC so trying to build for 1.8 with 21. So while targeting 1.8 API you can have some byte code/implem relying on jdk11+ internal function...

3. we also need to bump some tools/release manylinux docker, as well as tools/docker/[images,test] to built against 21 to be consistent when building release artifact...

[gchatelet]

For 1. this is now done at the .bazelrc level. So I think this is covered. Having a look at the rest.

[gchatelet]

Should be fixed, let me know if I missed something.