Add support to ROS 2 Components

[AntoBrandi]

Feature description

As all the Nav2 nodes support Composition we might really benefit from having the slam_toolbox nodes supporting composition as well

Implementation considerations

Composable Nodes might look like rtabmap_ros

~$ ros2 component types
rtabmap_slam
  rtabmap_slam::CoreWrapper
rtabmap_sync
  rtabmap_sync::RGBDSync
  rtabmap_sync::StereoSync
  rtabmap_sync::RGBSync
  rtabmap_sync::RGBDXSync
rtabmap_odom
  rtabmap_odom::RGBDOdometry
  rtabmap_odom::StereoOdometry
  rtabmap_odom::ICPOdometry
rtabmap_util
  rtabmap_util::RGBDRelay
  rtabmap_util::RGBDSplit
  rtabmap_util::LidarDeskewing
  rtabmap_util::PointCloudXYZ
  rtabmap_util::PointCloudXYZRGB
  rtabmap_util::PointCloudToDepthImage
  rtabmap_util::ObstaclesDetection
  rtabmap_util::PointCloudAggregator
  rtabmap_util::PointCloudAssembler

[AntoBrandi]

@SteveMacenski I addressed it here #652

[SteveMacenski]

Merged!