Fix 16K host page support

[ShadowCurse]

Changes

Separate PAGE_SIZE constant into 2: GUEST_PAGE_SIZE and HOST_PAGE_SIZE.
HOST_PAGE_SIZE has a default of 4K, but is also queried at runtime to support other page sizes.

The only structure which did not work with non default 4K pages is IovDeque. This PR updates it
and removes restrictions on the queue size and on the host page size.

Tested16K pages support on rp5 with 16K page kernel.

Reason

Previously Firecracker was working on hosts with non 4K pages, but with 1.10 version we introduced IovDeque type
which assumed the host page size to be 4K.

License Acceptance

By submitting this pull request, I confirm that my contribution is made under
the terms of the Apache 2.0 license. For more information on following Developer
Certificate of Origin and signing off your commits, please check
CONTRIBUTING.md.

PR Checklist

• I have read and understand CONTRIBUTING.md.
• I have run tools/devtool checkstyle to verify that the PR passes the
  automated style checks.
• I have described what is done in these changes, why they are needed, and
  how they are solving the problem in a clear and encompassing way.
• I have updated any relevant documentation (both in code and in the docs)
  in the PR.
• I have mentioned all user-facing changes in CHANGELOG.md.
• If a specific issue led to this PR, this PR closes the issue.
• When making API changes, I have followed the
  Runbook for Firecracker API changes.
• I have tested all new and changed functionalities in unit tests and/or
  integration tests.
• I have linked an issue to every new TODO.

---

• This functionality cannot be added in rust-vmm.

[codecov]

Codecov Report

Attention: Patch coverage is 88.57143% with 4 lines in your changes missing coverage. Please review.

Project coverage is 83.93%. Comparing base (70ac154) to head (ad8d232).

Files with missing lines	Patch %	Lines
src/firecracker/src/main.rs	0.00%	2 Missing ⚠️
src/vmm/src/arch/mod.rs	81.81%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4916      +/-   ##
==========================================
- Coverage   83.93%   83.93%   -0.01%     
==========================================
  Files         248      248              
  Lines       27791    27814      +23     
==========================================
+ Hits        23327    23345      +18     
- Misses       4464     4469       +5     

Flag	Coverage Δ
5.10-c5n.metal	84.51% <87.87%> (-0.01%)	⬇️
5.10-m5n.metal	84.50% <87.87%> (+<0.01%)	⬆️
5.10-m6a.metal	83.78% <87.87%> (+<0.01%)	⬆️
5.10-m6g.metal	80.61% <88.23%> (-0.01%)	⬇️
5.10-m6i.metal	84.48% <87.87%> (-0.01%)	⬇️
5.10-m7g.metal	80.61% <88.23%> (-0.01%)	⬇️
6.1-c5n.metal	84.51% <87.87%> (-0.01%)	⬇️
6.1-m5n.metal	84.50% <87.87%> (+<0.01%)	⬆️
6.1-m6a.metal	83.77% <87.87%> (-0.01%)	⬇️
6.1-m6g.metal	80.61% <88.23%> (-0.01%)	⬇️
6.1-m6i.metal	84.48% <87.87%> (-0.02%)	⬇️
6.1-m7g.metal	80.61% <88.23%> (-0.01%)	⬇️

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