Capture target Java release version in build time analytics

[rsvoboda]

Description

At this moment build time analytics capture version and vendor of java used for the build.

This can give slightly misleading data because people can be using Java 21 locally but the project can be still based on Java 11.

Build time analytics should be enhanced to capture and report target Java release version of the project.

CC @brunobat

Implementation ideas

Check value of maven.compiler.release for Maven projects, alternatively check source and target properties too, some people may be used to the old ones.
Check targetCompatibility in build.gradle file

Maybe there is a programmatic way to capture info on the target version, but I'm not aware of that.

[brunobat]

That's a good point.
Will add this to the pipeline.

[brunobat]

@geoand we should probably have a label for analytics subjects