also str representation of unicode character is different.

This only works on python2

for same reason as the xhtml_style version, there is no problem with
having more than one listbox, see d2dedca3 (core: remove useless log
in Base_callDialogMethod, 2020-07-03)

Use same label as the action, "Preview"

These scripts take time to run, so restrict them to Manager users.

See merge request !1928

See merge request nexedi/erp5!1915

  The render is useful to preview content after edit while doing a gadget or on other contexts.

  Since corportate identity has erp5_web as dependency, it cause no harm to move.