textproc/libxml2: bump all LIB_DEPENDS consumers

This is a separate commit to facilitate easier cherry-picking for
quarterly.

PR: 262853, 262940, 262877, 263126
Approved by: fluffy (mentor)

INSTALLS_ICONS: retire the macro and rework the related dependencies

While here, make sure gtk-update-icon-cache is only on run dependency
where added as a dependency
Enforce gtk3 to depend on gtk-update-icon-cache (previously it was
inheriting the dependency)

Remove # $FreeBSD$ from Makefiles.

Prefer graphics/ligvrsvg2-rust over graphics/librsvg2

- switch to the more modern version of librsvg2 on architectures
  supporting rust
- this will fix some graphical issues on these architectures

PR:		250276
Exp-run by:	antoine
Submitted by:	tobik
Differential Revision:	https://reviews.freebsd.org/D18878

x11-themes/gnome-themes-extra: avoid messing up STAGEDIR/plist failure

PR:		249429
Approved by:	freebsd-gnome (maintainer timeout, 15d)

The FreeBSD GNOME team proudly presents GNOME 3.28 for FreeBSD.

The offical GNOME 3.28 release notes can be found at
https://help.gnome.org/misc/release-notes/3.28/

Thanks to Antoine Brodin for running the exp-runs.

PR:		229761