erp5_run_my_doc: add slideshow editor gadget
This gadget only works in ERP5JS, as it depends on multiple ERP5JS only gadgets.
Some functionnalities have not been backported for now:
- image upload, which seems broken on xhtml style
- test template (I was not able to trigger something from the UI)
Normally, it could be possible to create an OfficeJS app with this editor.