chore: Custom Roles to manage permissions [ UI ] (#9865)

In admin settings, this Pr will add the UI for managing custom roles (
ref: https://github.com/chatwoot/chatwoot/pull/9995 ). It also handles
the routing logic changes to accommodate fine-tuned permissions.

---------

Co-authored-by: Pranav <pranavrajs@gmail.com>
Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>
Co-authored-by: iamsivin <iamsivin@gmail.com>
Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

app/views/api/v1/models/_user.json.jbuilder

@@ -30,5 +30,6 @@ json.accounts do
     # availability derived from presence
     json.availability_status account_user.availability_status
     json.auto_offline account_user.auto_offline
+    json.partial! 'api/v1/models/account_user', account_user: account_user if ChatwootApp.enterprise?
   end
 end