feat: Add APIs to manage custom roles in Chatwoot (#9995)

Co-authored-by: Pranav <pranavrajs@gmail.com>

enterprise/app/views/api/v1/models/_custom_role.json.jbuilder

@@ -0,0 +1,6 @@
+json.id custom_role.id
+json.name custom_role.name
+json.description custom_role.description
+json.permissions custom_role.permissions
+json.created_at custom_role.created_at
+json.updated_at custom_role.updated_at