Keep support for backends that support multiple pagesizes or remove it?

[Albert Astals Cid]

In Document we have
	bool supportsPageSizes() const
	PageSize::List pageSizes() const
	void setPageSize( const PageSize &size )

It is made to support document formats that don't really have a page size, so that the user can choose between them.

We also have UI to support this feature, the 
	aPageSizes = new KSelectAction(i18n("&Page Size"), this);
in PageView

The problem is that we don't have any backeng that supports this at the moment. The old ghostview generator used to, but when we moved to use spectre (billions of years ago) we lost this feature.

This means that if people add the "Page Size" action to a toolbar they don't ever get anything.

On the other hand, we have quite some backends like the "Markdown" that randomly say "my page size is QSizeF( 980, 1307 )" and thus could benefit from this feature of letting the user choose between A4, Letter, A5, or stuff.

So i was wondering:
 * Should we just remove all this support both from the core and the UI since it has not been used for 13 years
 * Keep it in hopes that $someone implements it for some of the text generators where it makes sense.

Addendum, maybe even if this feature makes sense for only *some* of the generators we should still remove it from the UI and if we implement it for some of the generators it should be part of the "Settings->Configure Backends" UI and not of the main UI.

Opinions?

Cheers,
  Albert