[RN] Detect errors when loading the configuration

The error is stored in the redux store in base/config so other components can
consult it. It is also broadcasted as a new event in the external API for the
SDK.

react/features/base/config/actionTypes.js

@@ -1,3 +1,14 @@
+/**
+ * The redux action which signals the configuration couldn't be loaded due to an
+ * error.
+ *
+ * {
+ *     type: LOAD_CONFIG_ERROR,
+ *     error: Error
+ * }
+ */
+export const LOAD_CONFIG_ERROR = Symbol('LOAD_CONFIG_ERROR');
+
 /**
  * The redux action which sets the configuration represented by the feature
  * base/config. The configuration is defined and consumed by the library

react/features/base/config/actions.js

@@ -1,6 +1,22 @@
 /* @flow */
 
-import { SET_CONFIG } from './actionTypes';
+import { LOAD_CONFIG_ERROR, SET_CONFIG } from './actionTypes';
+
+/**
+ * Signals an error when loading the configuration.
+ *
+ * @param {Error} error - The error which caused the config to not be loaded.
+ * @returns {{
+ *      type: LOAD_CONFIG_ERROR,
+ *      error: Error
+ * }}
+ */
+export function loadConfigError(error: Error) {
+    return {
+        type: LOAD_CONFIG_ERROR,
+        error
+    };
+}
 
 /**
  * Sets the configuration represented by the feature base/config. The