Fix startup crash and memory reporting to Xen

• Remove memreport to Xen to avoid Qubes trying to get back some memory (#176 @palainp, reported from Qubes forum[1], this also fixes #177 reported by @bluesteal and @xaki23)
• Use bookworm and snapshot.notset.fr debian packages for reproducibility (#175 @palainp, reported by @hannesm #165)

[1]: https://forum.qubes-os.org/t/new-usability-issues-dom0-processes-making-system-unusable/18301/2 and https://forum.qubes-os.org/t/memory-allocation-problem-remains-in-low-allocation-for-minutes/18787