Add support for the Gradle build scan using the Maven extension

The [Gradle Build Scan](https://scans.gradle.com/#maven) is a free service that provides useful insights regarding the project build (e.g., dependencies, plugins, tasks performance, tests, infrastructure used, etc.)
Once configured, the information is accessible via a randomly generated link, printed in the logs at the end of the build.
This information can be valuable for the community to better understand how Spoon is build.
For example, here's a view of the service after executing `mvn compile` on Spoon:


This service can be easily configured & integrated as part of the Spoon build using the official [Maven Extension](https://docs.gradle.com/enterprise/maven-extension/#build_scans_captured_information).

My question is the following: **Is this valuable for the Spoon project?**