We don't need two (and half) templating systems anymore, yay!
I'm keeping the changes minimal, to make the diff manageable. Some enhancements
due to a better templating system might be possible in the future.
For handling of '## ' — see the next commit.
Instead of enabling it unconditionally and then using ConditionPathExists=/etc/fstab,
and possibly masking this condition if it should be enabled for auto gpt stuff,
just pull it in explicitly when required.
The rule is that units that encapsulate our own code are prefixed with
"systemd-". Since the fsck units invoke our own code, hence add the
missing prefix. Since a long long time the fsck units didn't invoke the
naked fsck binaries anymore, and it is unlikely that this well ever
change. On the opposite: the code in systemd-fsck will probably get more
complex over time to handle fsck progress to plymouth forwarding.
Same for quotacheck (but not quotaon!)
