reorganize documentation tree and supplement with additional guides

docs/source/4_application_guide/tf_transformations.md

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+### TF from coordinate A to coordinate B:
+
+In Orbbec cameras, the origin point (0,0,0) is taken from the camera_link position
+
+Our wrapper provide static TFs between each sensor coordinate to the camera base (camera_link)
+
+Also, it provides TFs from each sensor ROS coordinates to its corrosponding optical coordinates.
+
+Example of static TFs of RGB sensor and right infra sensor of Gemini335 module as it shown in rviz2:
+
+```bash
+ros2 launch orbbec_description view_model.launch.py model:=gemini_335_336.urdf.xacro
+```
+
+![module in rviz2](../image/application_guide/image2.png)