include main page plus explanation to autoware tools

Signed-off-by: Muhammad Zulfaqar Azmi <zulfaqar.azmi@tier4.jp>

Author: zulfaqar-azmi-t4

common/.pages

@@ -1,15 +1,16 @@
 nav:
+  - 'Introduction': common
   - 'Testing Libraries':
     - 'autoware_testing': common/autoware_testing/design/autoware_testing-design
-    - 'fake_test_node': fake_test_node/design/fake_test_node-design
+    - 'fake_test_node': common/fake_test_node/design/fake_test_node-design
   - 'Common Libraries':
     - 'autoware_auto_common':
       - 'comparisons': common/autoware_auto_common/design/comparisons
     - 'autoware_auto_geometry':
       - 'interval': common/autoware_auto_geometry/design/interval
       - 'polygon intersection 2d': common/autoware_auto_geometry/design/polygon_intersection_2d-design
       - 'spatial hash': common/autoware_auto_geometry/design/spatial-hash-design
-    - 'autoware_auto_tf2': common/autoware_auto_tf2/design
+    - 'autoware_auto_tf2': common/autoware_auto_tf2/design/autoware-auto-tf2-design
     - 'autoware_point_types': common/autoware_point_types
     - 'Cuda Utils': common/cuda_utils
     - 'Geography Utils': common/geography_utils

common/README.md

@@ -0,0 +1,15 @@
+# Common
+
+## Getting Started
+
+The Autoware.Universe Common folder consists of common and testing libraries that are used by other Autoware components, as well as useful plugins for visualization in RVIZ2.
+
+!!! note
+
+    In addition to the ones listed in this folder, users can also have a look at some of the add-ons in the `autoware_tools/common` documentation [page](https://autowarefoundation.github.io/autoware_tools/main/common/mission_planner_rviz_plugin/).
+
+## Highlights
+
+Some of the commonly used libraries are:
+1. `tier4_autoware_utils`
+2. `motion_utils`