refactor: move getSetting from background.js -> helpers.js

this is because i plan to use it in `detailsInterface.js`

src/helpers.js

@@ -11,12 +11,32 @@ const BrowserpassURL = require("@browserpass/url");
 module.exports = {
     prepareLogins,
     filterSortLogins,
+    getSetting,
     ignoreFiles,
     makeTOTP,
 };
 
 //----------------------------------- Function definitions ----------------------------------//
 
+/**
+ * Get most relevant setting value
+ *
+ * @param string key      Setting key
+ * @param object login    Login object
+ * @param object settings Settings object
+ * @return object Setting value
+ */
+function getSetting(key, login, settings) {
+    if (typeof login.settings[key] !== "undefined") {
+        return login.settings[key];
+    }
+    if (typeof settings.stores[login.store.id].settings[key] !== "undefined") {
+        return settings.stores[login.store.id].settings[key];
+    }
+
+    return settings[key];
+}
+
 /**
  * Get the deepest available domain component of a path
  *