Refactor skills framework

Follow-up MRs:

• robot-skill-templates!48 (merged)
• armarx-simulation!66 (merged)
• sw/armarx/skills/control!37 (merged)
• sw/armarx/skills/kinesthetic-learning!2 (merged)
• sw/armarx/skills/localization-and-mapping!3 (merged)
• sw/armarx/skills/manipulation!33 (merged)
• sw/armarx-integration/robots/armar7/skills!8
• ... --> see comment

source/RobotAPI/components/skills/SkillProviderExample/Callback.cpp

@@ -12,7 +12,7 @@ namespace armarx::skills::provider
     {
         return SkillDescription{{"ShowMeCallbacks"},
                                 "This skill does shows callbacks",
-                                {},
+                                nullptr,
                                 armarx::core::time::Duration::MilliSeconds(1000),
                                 nullptr};
     }