feat(docs): style readme & add badges (#4970)

Centre Helix title and logo and add badge with latest
release and link to matrix chat.

README.md

@@ -1,8 +1,16 @@
+<div align="center">
+
 <img src="./logo.svg" height="128" alt="Logo"/>
 
 # Helix
 
 [![Build status](https://github.com/helix-editor/helix/actions/workflows/build.yml/badge.svg)](https://github.com/helix-editor/helix/actions)
+[![GitHub Release](https://img.shields.io/github/v/release/helix-editor/helix)](https://github.com/helix-editor/helix/releases/latest)
+[![Documentation](https://shields.io/badge/-documentation-452859)](https://docs.helix-editor.com/)
+[![GitHub contributors](https://img.shields.io/github/contributors/helix-editor/helix)](https://github.com/helix-editor/helix/graphs/contributors)
+[![Matrix Space](https://img.shields.io/matrix/helix-community:matrix.org)](https://matrix.to/#/#helix-community:matrix.org)
+
+</div>
 
 ![Screenshot](./screenshot.png)