Speeding up VM startups

Yeah, just thought that some part of the DVM initialization could be IO intensive.

I tried running the same command on my system, but I only have debian templates

$ time qvm-run --dispvm debian-11-dvm date
Running 'date' on $dispvm:debian-11-dvm

real	0m12.473s
user	0m0.037s
sys	0m0.021s
$ sudo systemd-analyze
Startup finished in 2.272s (kernel) + 3.110s (userspace) = 5.382s 
multi-user.target reached after 2.111s in userspace