OpenJDK 11: migrate to Java 9+ modules system

Part of #6197

Packages and dependency compatibility issues can cause compilation errors (example: different packages uses same dependency/module and can't be compiled by newest java, see #6809):
* `The package org.w3c.dom.events is accessible from more than one module: , java.xml`

[The problem in missing `module-info.java` files](https://stackoverflow.com/a/53824670/1276632) -- new Java 9+ modules system. Project must be migrated to it to support newest java versions.