* update pot files

* retrieve last transifex translations

* remove empty po file

* add translation coverage badge

* fix invalid po files

On HiDPI displays, rendered pages use more memory than the cache budget
expects because the size calculation does not account for the device
scale factor. This causes the cache to use up to 4x more memory than
configured on 2x HiDPI displays.

Using 50 MiB is not enough to show an A0-sized document in a HiDPI
display. This bumps the page cache size to 500 MiB to provide enough
headroom. This memory is not pre-allocated, it just provides a safety
limit.

Cairo surfaces have a limit of 32767px in any dimension, so we make sure
that we don't end up zooming in past the point where the rendered
surface is larger than that limit.

Measuring image dimensions based on rotation is unnecessary, since the
result is either w×h or h×w, which is commutative.

The EphyZoom widget uses logical zoom (eg. 100%)  while the libview widget uses
physical zoom, that is if logical zoom is 100% then scale will be 100%*dpi/72.0.

Backported from https://gitlab.gnome.org/GNOME/evince/-/commit/0a0a2d8c

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