Feature request: Infinite scroll mode

[Compro Prasad]

The PDF readers like `evince` on GNOME have continuous scroll mode
which is favorable while reading stuff. But Emacs can't afford that
because of the buffer concept.

It would be great to have a mode which lets the user/package to utilize
an infinite buffer space where we can place text and images as we wish.

A restriction of adding stuff to the left might not be necessary because
of indentation but it may be an option too. After deactivating the mode
the extra space from top, bottom and the sides will be removed so that
we cannot add stuff to outer space just by magic.

https://github.com/politza/pdf-tools/issues/27
The above issue is just sitting there and Emacs has no option about it
as far as I can guess. If there is an option to solve the above issue
then it would be a pleasure to hear about it.

Abhishek(Compro) Prasad