Allow qube to reboot upon its request

[ben-grande]

Fixes: QubesOS/qubes-issues#8196

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Missing some method to make qmemman hold the memory of the domain and not redistribute it (until timeout is reached).

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Rusty Bird note about the default: If True, a malicious qube can exceed the revisions_to_keep by keeping rebooting, and prevent restoration to a known good state. See linked issue for the dicussion.

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• ran OpenQA on my runner
• rebooted HVM, TemplateVMs and StandaloneVMs but required libvirt_domain.destroy():
  • Windows 11
  • Ubuntu Desktop 26.04
  • OpenBSD 7.9
  • fedora-, debian- (Any TemplateVM)

[codecov]

Codecov Report

❌ Patch coverage is 23.52941% with 26 lines in your changes missing coverage. Please review.
✅ Project coverage is 70.17%. Comparing base (71b5ab2) to head (6649f40).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
qubes/vm/qubesvm.py	32.00%	17 Missing ⚠️
qubes/app.py	0.00%	5 Missing ⚠️
qubes/tools/qmemmand.py	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #810      +/-   ##
==========================================
- Coverage   70.24%   70.17%   -0.07%     
==========================================
  Files          61       61              
  Lines       14073    14097      +24     
==========================================
+ Hits         9885     9893       +8     
- Misses       4188     4204      +16     

Flag	Coverage Δ
unittests	70.17% <23.52%> (-0.07%)	⬇️

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