docs(readme): enrich readme

README.md

@@ -1,7 +1,9 @@
 # autoware.universe
 
-For Autoware's general documentation, see [Autoware Documentation](https://autowarefoundation.github.io/autoware-documentation/).
+Welcome to Autoware.universe! This platform is a pivotal element within the core/universe concept of Autoware, managing a diverse range of packages that extend the core functionalities of autonomous driving.
 
-For detailed documents of Autoware Universe components, see [Autoware Universe Documentation](https://autowarefoundation.github.io/autoware.universe/).
+![autoware_universe_front](docs/assets/images/autoware_universe_front.png)
 
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+The code and documentation managed here represent a vital part of the Autoware ecosystem. To gain a comprehensive understanding of the entirety of Autoware, please visit the [Autoware Documentation](https://autowarefoundation.github.io/autoware-documentation/).
+
+For detailed documents of Autoware Universe components, see [Autoware Universe Documentation](https://autowarefoundation.github.io/autoware.universe/) deployed by MKDocs.