Remove obsolete hard-coded publishing panel fields

[benfroelich]

wagtailmenus recreates wagtail's scheduled publishing (go-live and expiry) fields here:

wagtailmenus/wagtailmenus/panels.py

Lines 114 to 127 in bd7d426

	menupage_settings_panels = [
	MultiFieldPanel(
	heading=_("Scheduled publishing"),
	classname="publishing",
	children=(
	FieldRowPanel((
	FieldPanel('go_live_at', classname="col6"),
	FieldPanel('expire_at', classname="col6"),
	)),
	)
	),
	menupage_panel,
	]

Furthermore MenuPage overrides, instead of appends to, Page's settings_panels:

wagtailmenus/wagtailmenus/models/pages.py

Lines 133 to 136 in bd7d426

	class MenuPage(Page, MenuPageMixin):
	settings_panels = menupage_settings_panels

So you end up with deprecated scheduled publishing fields and also excluded features such as privacy and comments which are now in a sidebar popout, at least in wagtail 4.1.1.

I believe the fix is to (1) append the wagtailmenus advanced menus fields to Page's settings_panels and (2) remove the duplicated scheduled publishing fields.

I am working on a PR now. Please let me know if I'm off on this. Thanks!

[benfroelich]

BTW, for now the workaround I'm using until the official package gets updated is to override settings_panels as shown on my MenuPage derived models:

class BlogPost(MenuPage):
    # TODO: revert when wagtailmenus is updated
    settings_panels = Page.settings_panels + MenuPage.settings_panels
    ...

[benfroelich]

#441