refactor: split common until and add ut

src/shared/utils/index.js

@@ -7,10 +7,13 @@ export * from './avatar';
 export * from './chart';
 export * from './common';
 export * from './compare';
+export * from './fileUtils';
 export * from './friend';
 export * from './group';
 export * from './instance';
+export * from './platformUtils';
 export * from './setting';
+export * from './urlUtils';
 export * from './user';
 export * from './gallery';
 export * from './location';