Gradle migration

[svengreb]

The project should migrate from Maven to Gradle for a simplified workflow and setup following large projects like Android. This will improve the development in various aspects as described in the documented Gradle vs Maven comparison.

The Gradle Docs are very well written and almost everything is documented. There are many resources e.g. guides about how to

• migrate from Maven
• write build scripts
• use a plugin to keep up the compatibility with Maven repositories