feat(core): 将goog.get接口调整为goog.readJsonSync以指示其同步操作特性

common/modules/mixly-modules/common/loader.js

@@ -48,7 +48,7 @@ window.addEventListener('load', () => {
     }
     const app = new App($('body')[0]);
     Mixly.app = app;
-    const $xml = $(goog.get(Env.boardIndexPath));
+    const $xml = $(goog.readFileSync(Env.boardIndexPath));
     let scrpitPaths = [];
     let cssPaths = [];
     let $categories = null;