backend: automatically restart services in %post
I asked on `#fedora-devel` about restarting a target and the response
was "What would restarting target even mean?". I also didn't find any
mentions of restarting targets in the documentation.
The `man systemd.target` doesn't go into detail about the possible
use-cases of targets, it only mentions "grouping units and as
well-known synchronization points during start-up."
ArchWiki even equates targets to SysV runlevels,
https://wiki.archlinux.org/title/systemd#Targets
so in this context, restarting targets doesn't make sense as well.
I don't know if our `copr-backend.target` is a valid use-case but it
IMHO doesn't matter. We can file a RFE for supporting targets in
`%systemd_postun_with_restart` but for the time being, I would just
change our specfile and list all services that should be restarted.
Fix: #2141
Merges: #2164