Multi-class objects not visualized correctly

[bastilam]

Current behavior:

• If if the ObjectClassification vector of an object contains multiple classifications, only one is visualized in RViz, even if they have equal probabilities.

Expected behavior:

• Suggestion: For equal probabilities, show all classes, e.g.: bicycle | motorcycle
• Probably already the case: For unequal probabilities, show the most probable class.
• Bonus: Let the user configure in RViz how these cases are visualized.