docs(readme): enrich readme (autowarefoundation#6518)

Signed-off-by: Takamasa Horibe <[email protected]>

README.md

@@ -1,7 +1,16 @@
-# autoware.universe
+# Autoware Universe
 
-For Autoware's general documentation, see [Autoware Documentation](https://autowarefoundation.github.io/autoware-documentation/).
+## Welcome to Autoware Universe
 
-For detailed documents of Autoware Universe components, see [Autoware Universe Documentation](https://autowarefoundation.github.io/autoware.universe/).
+Autoware Universe serves as a foundational pillar within the Autoware ecosystem, playing a critical role in enhancing the core functionalities of autonomous driving technologies.
+This repository is a pivotal element of the Autoware Core/Universe concept, managing a wide array of packages that significantly extend the capabilities of autonomous vehicles.
 
----
+![autoware_universe_front](docs/assets/images/autoware_universe_front.png)
+
+## Getting Started
+
+To dive into the vast world of Autoware and understand how Autoware Universe fits into the bigger picture, we recommend starting with the [Autoware Documentation](https://autowarefoundation.github.io/autoware-documentation/). This resource provides a thorough overview of the Autoware ecosystem, guiding you through its components, functionalities, and how to get started with development.
+
+### Explore Autoware Universe documentation
+
+For those looking to explore the specifics of Autoware Universe components, the [Autoware Universe Documentation](https://autowarefoundation.github.io/autoware.universe/), deployed with MKDocs, offers detailed insights.