Configure java modules

[nmandrescu]

About
Java module system.
jdeps can help to generate module-info.java, alternatively IntelliJ helps much in manual process.

Benefits

• General java module benefits
• Allow to open reflective access to specific module(s) only instead of ALL-UNNAMED. This explicit opening needed since JDK17+.

Pitfalls

• springfox uses split packages and this issue is not yet addressed.
• we use both ooxml-schemas and poi-ooxml. A split package detected for xmlbeans inside (though xmlbeans is excluded in web/pom.xml).
• TBD

Though we can remove such dependencies, later we may still need a problematic lib. A workaround can be to merge such lib with --patch-module.