Latest tutor prints very funny package names instead of clean names

[jurgenvinju]

Describe the bug

This is listing the contents of java-air.jar after running mvn package:

docs/Packages/Org.rascalmpl:java-air:jar:1.0.0-RC3-SNAPSHOT/License.md
docs/Packages/Org.rascalmpl:java-air:jar:1.0.0-RC3-SNAPSHOT/RELEASE-NOTES.md
docs/Packages/Org.rascalmpl:java-air:jar:1.0.0-RC3-SNAPSHOT/index.md

Before this used to be:

docs/Packages/JavaAir/License.md
docs/Packages/JavaAir/RELEASE-NOTES.md
docs/Packages/JavaAir/index.md

Ideally we should change it to something that remains valid for the future:

docs/Packages/org.rascalmpl.java-air/License.md
docs/Packages/org.rascalmpl.java-air/RELEASE-NOTES.md
docs/Packages/org.rascalmpl.java-air/index.md

• the version is irrelevant because we only document one version on the website
• the groupid will become relevant when we start accepting more third-party packages