add integrity checks for remote configuration

[vdeturckheim]

What does this PR do?

This PR introduces TUF-like integrity checks for upcoming Remote configuration updates.

[codecov[bot]]

Codecov Report

Merging #2236 (289c330) into master (6ec08d6) will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2236   +/-   ##
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  Coverage   93.44%   93.44%           
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  Files         218      218           
  Lines        8334     8334           
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  Hits         7788     7788           
  Misses        546      546           

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[rochdev]

Just had a chat with @vdeturckheim and I now better understand what this is all doing. However, given how critical this code is, I would say to move it to some internal module (for example packages/tuf) that we could later on convert to an external library, and add as many links as possible in comments to what this is implementing.

[trishankatdatadog]

@kommendorkapten we could use tuf.js from sigstore.js in the near future 🙂

[tlhunter]

@cedricvanrompay-datadog @trishankatdatadog would either of you two be interested in wrapping up this PR? If not, is it safe to close?

[simon-id]

Please do not delete. We still haven't decided that integrity checks must be done in the library, but if it happens one day I want to use this PR.