ROS2 various QOL updates (preparing new binary release) (#1225)

* Updating examples and README

* updated main readme

* odom: Added always_check_imu_tf parameter. sync: increased default sync_queue_size from 2 to 5 (to be more flexible to different hardware), added input and output diagnostics. rtabmap_viz: fixed node with same name redeclared warning.

* update readme

* Added husky demo

* converted demo_robot_mapping.launch to ros2

* Converted stereo_outdoor demo from ros1 to ros2

* Converted multi-session demo to ros2

* Converted demo_find_object launch to ros2

* renamed files

* uniformized default qos, increased sync_queue_size default to 10

* Added vlp16 + imu example

* Added husky 3D lidar demos

* moved demos in subdir

* Added vlp16+zed example

* rtabmap_viz: ignore odom update if tf not ready when not using topic (to avoid showing red screen). Added champ VSLAM demo.

* forwarded camera_model arg for zed examples, removed qos for turtlebot4 demo

* pointcloud_to_depthimage: added more error logs, removed output camera_info published twice and match ros1 namespaces

* Created two base general examples for 3D lidar usage, then create hardware specific examples on top of them.

* Added isaac sim demo

* Final update of all demos. Fixed MapCloud rviz plugin crashing when floor/ceiling filtering is used and resulting cloud is empty.

* Fixed 2d scan deskewing output frame, moved nav2 params under "params" folder, added number of topics processed/dropped for odometry, added icp_odometry option for turtlebot3 scan-only demo.

* rtabmap_demos: added README with examples

* Added TOC

* bump version to 0.21.9

rtabmap_launch/README.md

@@ -0,0 +1,40 @@
+
+
+# Usage
+
+`rtabmap.launch` from ros1 has been ported to ROS2 as `rtabmap.launch.py` with same arguments. If you see [ROS1 examples](http://wiki.ros.org/rtabmap_ros/Tutorials/HandHeldMapping) like this:
+
+```bash
+roslaunch zed_wrapper zed_no_tf.launch
+
+roslaunch rtabmap_ros rtabmap.launch \
+    rtabmap_args:="--delete_db_on_start" \
+    rgb_topic:=/zed/zed_node/rgb/image_rect_color \
+    depth_topic:=/zed/zed_node/depth/depth_registered \
+    camera_info_topic:=/zed/zed_node/rgb/camera_info \
+    frame_id:=base_link \
+    approx_sync:=false \
+    wait_imu_to_init:=true \
+    imu_topic:=/zed_node/imu/data
+
+```
+
+The ROS2 equivalent is (using latest zed_wrapper launch file):
+
+```bash
+ros2 launch zed_wrapper zed_camera.launch.py camera_model:=zed2i \
+    publish_tf:=false \
+    publish_map_tf:=false
+
+ros2 launch rtabmap_launch rtabmap.launch.py \
+    rtabmap_args:="--delete_db_on_start" \
+    rgb_topic:=/zed/zed_node/rgb/image_rect_color \
+    depth_topic:=/zed/zed_node/depth/depth_registered \
+    camera_info_topic:=/zed/zed_node/rgb/camera_info \
+    frame_id:=zed_camera_link \
+    approx_sync:=false \
+    wait_imu_to_init:=true \
+    imu_topic:=/zed/zed_node/imu/data \
+    rviz:=true
+```
+