`TranspileMojo` does not generate `package-info.java` for packages without `.eo` files

[maxonfjvipon]

Consider this sources structure:

- org
    |- eolang
        |- number.eo

After transpile step in generated-sources directory we will have the next files:

- EOorg
    |- EOeolang
        |- EOnumber.java
        |- package-info.java

As you see - there's package-info.java file only in EOorg.EOeolang package, because number.eo contains +package org.eolang meta. There are 2 problems:

1. after unspile step EOorg/EOeolang/package-info.class file is deleted because it's present in generated-sources
2. if eo sources file structure is different from java sources structure - we don't have package-info.class in target/classes after compilation

As the result - our package is published to maven central without package-info.class files in some packages.