This way we can reset a lesson using the database for each user and not for all users at once.
Also solves the issue that when someone solves the lesson it is solved for all users on the same WebGoat instance
* Remove method `getId()` from all lessons as it defaults to the class name
* remove clean up endpoint
* remove unused class `RequestParameter`
* remove unused class `PluginLoadingFailure`
* Move `CourseConfiguration` to lesson package
* Add more content around the lesson template lesson and make it visible as a lesson in WebGoat
* Remove explicit invocation `trackProgress()` inside WebGoat framework so assignments only need to return an `AttackResult`
* Put original solution back as well for SQL string injection
* review comments
* Add
* Remove Guava dependency from WebGoat
* Add Checkstyle to the project with very basic standards so we have a
style across lessons. It does not interfere with basic Intellij formatting
