Improve Developer experience (mostly ERP5 Workflow/Python Scripts)

Fixes [#20210517-960A47](https://erp5js.nexedi.net/#/bug_module/20210517-960A47)

The most important changes are:
 - coding style is enabled again for workflow scripts and starts to be enabled for ERP5 Python scripts
 - monaco editor support for workflow scripts, SQL methods and .less
 - small fixes for python/workflow scripts forms and ZMI

See merge request nexedi/erp5!1422