docs: add logo and update README with logo inclusion

Include a new logo in the documentation and update the README
to feature this logo at the beginning. This change enhances
branding and visual appeal, making the project presentation more
professional and recognizable.

Author: DefinitelyADev

README.md

@@ -1,4 +1,6 @@
-# Custom Areas Integration for Home Assistant
+![Custom Areas Integration](/docs/images/logo.svg "Custom Areas Integration Logo")
+
+# Custom Areas Integration
 
 A custom integration for Home Assistant that creates composite "Area" sensors with UI configuration.