Implement get group settings method

src/controllers/groups_controller.rs

@@ -76,5 +76,10 @@ pub fn get_advanced_info(r: &mut HttpRequestHandler) -> RequestResult {
 
 /// Get the settings of the group
 pub fn get_settings(r: &mut HttpRequestHandler) -> RequestResult {
-    r.success("implement me")
+    let group_id = r.post_group_id_with_access("id", GroupAccessLevel::ADMIN_ACCESS)?;
+    let group = groups_helper::get_info(&group_id)?;
+
+    // For now, this method is the same as the get advanced info method,
+    // but this might change in the future...
+    r.set_response(AdvancedGroupApi::new(&group, r.user_id_opt())?)
 }