Feature/aanno small gradle improvement

[aanno]

Dear AsamK,

here are some gradle build improvements that I found useful when using your great signal-cli:

1. Provide a (maven) group for signal-cli and lib from gradle.properties
2. Provide the version for signal-cli and lib from gradle.properties
3. Pack a generated pom.xml with both jars (the way it would be if the jars are generated with maven). This would help dependency management if the jars are used in other projects.
4. Provide a distribution zip and tar (with all dependencies packed). This will simply the use of signal-cli as user.
5. Add a 'Automatic-Module-Name' entry to the manifest. This is helpful if the jars are used as dependencies in a Java 11 module-system project.
6. Add a 'Maven-Group' entry to the manifest.

Perhaps you find some of this suggestions useful.

Kind regards,

aanno