Add minimal pick-and-place case with world embedded

rbs_simulation/CMakeLists.txt

@@ -12,10 +12,12 @@ find_package(ament_cmake REQUIRED)
 # find_package(<dependency> REQUIRED)
 
 install(
-  DIRECTORY launch
+  DIRECTORY launch worlds
   DESTINATION share/${PROJECT_NAME}
 )
 
+add_subdirectory(models)
+
 if(BUILD_TESTING)
   find_package(ament_lint_auto REQUIRED)
   # the following line skips the linter which checks for copyrights