improve trafficlight cpp example

[tangele]

https://github.com/Yakindu/examples/tree/master/org.yakindu.sct.examples.trafficlight.cpp

• make path consistent with project name
• index.html should contain explanations for QT.
• metadata.json should also contain notes about QT.
• improve index.html what the purpose of this example is
  • cpp code + c code generator

[tkutz]

We removed that example in favor of the already existing Qt/C++ example.