dtable accessToken (#3953)

* get dtable accessToken

* add testcase

* change token load method

* repair code error

* update dtable version

frontend/src/view-file-dtable.js

@@ -17,7 +17,7 @@ window.dtable = {
   filePath: filePath,
   fileName: fileName,
   dtableUuid: dtableUuid,
-  accessToken: '12345678'
+  accessToken: ''
 };
 
 window.seafileAPI = seafileAPI;