If the current zoom level was within one zoom factor of the limit, it
was not possible to scroll towards the limit. This made smooth scrolling
near the limit awkward, as unless the scroll event had a large delta it
was impossible to reach the zoom limit. Non-smooth scrolling was also
affected, but it was just much more difficult to trigger.

Fix this by allowing zooming while the current zoom level is within one
zoom factor of the limit. Add a new ev_view_can_zoom() function to make
zooming by a factor (as with smooth scrolling) more convenient.

Backported from https://gitlab.gnome.org/GNOME/evince/-/commit/6d299b69

This simplifies the logic required to enable zoom actions for
consumers of the view.

Backported from https://gitlab.gnome.org/GNOME/evince/-/commit/bbfbf913

shell: Add EvFindSidebar widget to show search results
see https://gitlab.gnome.org/GNOME/evince/-/commit/940ce8048e4fc6503dca03c1ce090ff4a11dface

eggfindbar: don't close the findbar when it loses the focus
see https://gitlab.gnome.org/GNOME/evince/-/commit/a2d781fb124bd19861035fd41dacc976e00d19ef

shell: Add the findbar to the main box instead of the view box

libview: Add ev_view_find_set_result

Not everyone who reads PDF's is necessarily a LaTeX user.
These changes allow users to install atril without the huge bagage
of tex-live on systems where synctex isn't provided as a stand alone
library.

This reverts commit 00fad2c0d0fcdade570a08f046e85a4558f1fc0c.

and fixes https://github.com/mate-desktop/atril/issues/404