[FEAT] Successfully controlling robot arm

Created by: otischung

1. Create an ArmManager global pointer.
2. Initialize the ArmManager in create_entities().
3. Also delete the ArmManager in destroy_entities().
4. Increase the rmw_uros_ping_agent(500, 1) from 100 to 500ms.
5. Increase the arm movement step to increase the speed.
6. Add build flags to prevent timeout Set RMW_UXRCE_ENTITY_CREATION_DESTROY_TIMEOUT=0 to prevent timeout of create_entities().