Support importing distro-installed packages

[KOLANICH]

Some distros install jars into some location within FS. We may want to know such locatiins for different distros and load packages of any versions from there.

For example

/usr/share/java/antlr4-runtime.jar
/usr/share/java/antlr4-runtime-4.7.2.jar
/usr/share/maven-repo/org/antlr/antlr4-runtime/4.7.2/antlr4-runtime-4.7.2.jar
/usr/share/maven-repo/org/antlr/antlr4-runtime/debian/antlr4-runtime-debian.jar

on Debian-based distros. As you see, the last path contains no version. And other path contain.

scyjava (or I guess it may make sense to move this jar-discovery functionality into a separate package) should be able to check these dirs (and also user-provided dirs) for jars with needed packages using the naming conventiins used in distros.