Refactor "jstreetable.js" and update the renderer

- Remove redundant and not-working customization
  that modifies the "jstree-table-wrapper" style.
  "jstreetable.js" doesn't provide any minimum
  version so that MFR has to use the full one and
  refactor it with "eslint" and add docstr.
- Minor updates for the renderer:
  - Enable cache which was disabled for local test
  - Update column width for file size
  - Use closed-folder icon
  - Remove unused assets

Author: cslzchen

mfr/extensions/zip/render.py

@@ -21,7 +21,7 @@ def file_required(self):
 
     @property
     def cache_result(self):
-        return False
+        return True
 
     def render(self):