Make it possible to have multiple JDKs installed of the same version

[quintesse]

This would make it possible to have multiple JDKs of the same major version (eg. multiple version 21s). There would still be a "default" per version, meaning that if someone says --java 21 or the code has //JAVA 21 we still know for sure which version is going to be used (and that default can be changed by the user of course)

Depends on jbangdev/jbang-devkitman#46