Major - Fix connection leak in MySQL statistics updater (✓ don't use a connection only for a print out)
- Solve SonarQube blocker vulnerabilities especially XML readers, parsers and transformers (✓)
- Remove redondant generics (like List<String> a = new ArrayList<String>()) (✓)
- Remove old TODOes, not understandable TODOes, TODOes without explanations... (✓)
- Remove type="text/javascript" and type="text/css" (✓)
