Feature request

Feature description

• Currently, the action_server_name is passed as an argument to the constructor, and the action_client is initialized in the constructor.
• In this implementation the action client is reinitialized with a remapped_action_name. However, this wouldn't work unless the default action server is available. Otherwise, the code will get blocked at the constructor of BtActionNode

Implementation considerations

• Ideally, I would like it to be implemented just as how service_name is passed in BtServiceNode
• However, this could change the signature of BtActionNode, and could lead to errors to the ones already using it.