FEAT: Adding `ros2:rcl_node_init` traceback

[wkaisertexas]

This tracepoint is called whenever a node is created and would allow me to associate a vpid to a node_name and a node_namespace

DEFINE_TRACEPOINT(
  rcl_node_init,
  TRACEPOINT_PARAMS(
    const void * node_handle,
    const void * rmw_handle,
    const char * node_name,
    const char * node_namespace),
  TRACEPOINT_ARGS(
    node_handle,
    rmw_handle,
    node_name,
    node_namespace))

Right now I am using procname which is limited in size, so I am getting the truncated node name. This is fine for internal use at cavauto, but having the full node name and namespace would be nice.