Long hostnames result in qubesdb paths that exceed the current 64
character limit.  Instead of crashing the firewall daemon, log the error
and continue without adding the hostname to the DNS records.

This is a workaround, not a fix, for
https://github.com/QubesOS/qubes-issues/9084.  The fix requires either
longer path support in qubesdb or using a different schema so that keys
will not exceed the qubesdb path length limit.

New template updater (core-admin-linux vmupdate)
uses tar for extracting update agent files.
But currently tar is not dependency of Qubes core components,
so people maybe remove it mistakenly.
Adding tar to core-agent dependencies will
reduces such risks.

On Fedora 42, `script` executable is moved to `util-linux-script`
package. It is required for `qubes-download-dom0-update.sh` to work.

When 'vif-route-qubes offline' is called, the interface (usually)
doesn't exist anymore. In that case, commands are called with
'do_without_error', but while it doesn't fail the script, it still logs
misleading error message.

Avoid calling 'ip' on non-existing interface to remove its
address/route, as those are removed by the kernel implicitly anyway.
But still call them on online action (if interface doesn't exist at this
point, it will fail, and that's intentional to get proper error
message), or when the interface still exist at the time the script is
called (in which case, it may still race against disappearing the
interface, but then there is 'do_without_error' prefix as the
last resort). This way, it avoids confusing error in the common case,
but still ensure things are cleaned up in the unusual case of interface
staying there.

* origin/pr/561:
  Assure `script` is installed for dom0 update

* origin/pr/560:
  qubes-core-agent: add tar to dependencies

* origin/pr/559:
  Fix the issue URL in the log message
  Remove accidentally duplicated test function
  firewall: avoid crash on qubesdb long path errors