added Welcome page

changed settings API and page to React + rest
changed structure of scripts - different folders for editor and admin scripts

src/admin/store/settings/index.js

@@ -0,0 +1,19 @@
+/**
+ * Internal dependencies
+ */
+import reducer from './reducer';
+import * as actions from './actions';
+import * as selectors from './selectors';
+
+/**
+ * WordPress dependencies
+ */
+import { createReduxStore, register } from '@wordpress/data';
+
+const store = createReduxStore('mind/settings', {
+	reducer,
+	actions,
+	selectors,
+});
+
+register(store);