[documentation] update the logo and make readme header cleaner (#384)

* docs: update the logo and make readme header cleaner

Signed-off-by: badaljain <badal.jain77@gmail.com>

* docs: handle dark and light mode logos

Signed-off-by: badaljain <badal.jain77@gmail.com>

* chore: remove spacing

Signed-off-by: badaljain <badal.jain77@gmail.com>

---------

Signed-off-by: badaljain <badal.jain77@gmail.com>

Author: badaljain

README.md

@@ -1,6 +1,14 @@
-<img alt="LitmusChaos" src="https://avatars.githubusercontent.com/u/49853472?s=200&v=4" width="200" align="left">
+<div align="center">
 
-# Documentation for the Litmus Project
+  <picture>
+    <source media="(prefers-color-scheme: dark)" srcset="https://litmuschaos.io/logos/light-logo.svg">
+    <source media="(prefers-color-scheme: light)" srcset="https://litmuschaos.io/logos/dark-logo.svg">
+    <img alt="LitmusChaos" src="https://litmuschaos.io/logos/dark-logo.svg" width="200">
+  </picture>
+
+  <h1 style="margin-top: 20px; margin-bottom: 10px;">Documentation for the Litmus project</h1>
+
+</div>
 
 [![FOSSA Status](https://app.fossa.com/api/projects/git%2Bgithub.com%2Flitmuschaos%2Flitmus-docs.svg?type=shield)](https://app.fossa.com/projects/git%2Bgithub.com%2Flitmuschaos%2Flitmus-docs?ref=badge_shield)
 [![Slack Channel](https://img.shields.io/badge/Slack-Join-purple)](https://slack.litmuschaos.io)
@@ -20,8 +28,6 @@
 
 Additional details on the Docusaurus project can be found [here](https://docusaurus.io/docs/en/installation.html).
 
-#
-
 ## For Developers
 
 ### Clone litmus-docs repository