community/libvirt: refactor dependencies, critical bugfix

• introduce maintainer variable
• add iproute2-tc dependency to -daemon subpackage (fixes #16749 (closed)) https://packages.fedoraproject.org/pkgs/libvirt/libvirt-daemon-common/fedora-rawhide.html https://packages.debian.org/sid/libvirt-daemon-system
• add 5.5.0 as minimal version for qemu https://www.libvirt.org/news.html#v10-6-0-2024-08-05
• remove empty -uml driver pkg, as it has been dropped upstream https://www.libvirt.org/news.html#v5-0-0-2019-01-15
• remove jansson-dev makedepends, dropped by upstream https://gitlab.com/libvirt/libvirt/-/commit/86db0db979c39df278f03dbf3b4239c873ddb637
• remove libgcrypt-dev makedepends, dropped by upstream https://gitlab.com/libvirt/libvirt/-/commit/279a27d4aaba9002c0342bf1ce251407713f105e
• remove libgpg-error makedepends, never needed
• move libxslt dependency to _client_deps, containing xsltproc needed at runtime
• remove util-linux makedepends, never needed
• remove zlib-dev makedepends, never needed

fixes: #16749 (closed)

cc: @team/mentors