[renderjs_ui] Extract utility function ensureArray, getFirstNonEmpty, and isEmpty into global gadget

/reviewed-on nexedi/erp5!570

This will increase the information's density for desktop users

-  use field defined CSS class on the top-level div only
-  compute correct paddings for horizontal elements

/reviewed-on !566

Iframe are only used with the editors, which now have a maximize feature

Add Base_renderForm to bypass erp5_hal_json_style limitations: it is not possible to render a field in JSON by directly using it as a callable.

[erp5_crm_renderjs_ui_test] Test create response dialog

This will prevent the input gadget to be changed if its parent call render with the same value (as ERP5 does in case of formulator error).

Display the update button if an action is defined.
Send the 'update_method' in the query in this case.

/reviewed-on nexedi/erp5!559