sysconfig/cloudinit: Check if disabled via kernel commandline

[holmanb]

Currently snapd manually checks for the presence of /etc/cloud/cloud-init.disabled to avoid running cloud-init status. This is done to avoid having to run cloud-init status to check current status. Similarly, snapd can check the kernel commandline for cloud-init=disabled which also disables cloud-init permanently.

A unit test is included.

[github-actions[bot]]

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[holmanb]

@bboozzoo Thanks for the review. I just rebased on the tip of master and pushed the requested changes.

Ready for re-review.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 78.86%. Comparing base (8d91db0) to head (8ffe03f). Report is 1 commits behind head on master.

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Additional details and impacted files

@@            Coverage Diff             @@
##           master   #13289      +/-   ##
==========================================
- Coverage   78.88%   78.86%   -0.02%     
==========================================
  Files        1037     1037              
  Lines      132876   133056     +180     
==========================================
+ Hits       104823   104940     +117     
- Misses      21515    21562      +47     
- Partials     6538     6554      +16     

Flag	Coverage Δ
unittests	78.86% <100.00%> (-0.02%)	:arrow_down:

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[holmanb]

Thanks @bboozzoo @Meulengracht @ernestl for the reviews. I think that I've addressed everything.

[holmanb]

It looks like this is waiting for a review from @alfonsosanchezbeato. I believe that I've addressed all requested changes. Please let me know anything else needs to change.

[ernestl]

@Meulengracht, is review from Alfonso still required here?

[Meulengracht]

I think it's okay to land

[ernestl]

Proposed replacement PR for rebase & conflict fix: https://github.com/snapcore/snapd/pull/13289