VIDSOL-165: web documentation for configurable features (#248)

Author: johnny-quesada-developer

README.md

@@ -73,6 +73,12 @@ This application provides features for common conferencing use cases, such as:
 
     <img src="docs/assets/BGEffects.png" alt="Screenshot of background effects">
   </details>
+- <details>
+    <summary>
+      Configurable features: adapt the app to your specific use cases and roles.
+      Configuration is handled through a <em>config.json</em> file that can be moved to the <em>frontend/public</em> folder; there's an example in the base directory, <em>config.example.json</em>. Changes to the config file will be reflected immediately in most cases, but some rooms will need to be re-joined to take effect (For example: "setting the default layout" or "audio on join").
+    </summary>
+    <img src="docs/assets/configFile.png" alt="Screenshot of a config.json">
 - <details>
     <summary>Composed archiving capabilities to record your meetings.</summary>
     <img src="docs/assets/Archiving.png" alt="Screenshot of archiving dialog box">