migrate message encryption to AEAD (AES‑GCM) + HKDF

[naiming-zededa]

Description

• replace the legacy encryption path with AEAD (AES-GCM) and derive per-session AES keys with HKDF-SHA256.
• if configured with encryption, force explicit nonce/cipher validation
• fix a yetus complaint

PR dependencies

How to test and validate this PR

• first, need to enable the Edgeview policy (for the project or for specific edge-node) w/ 'Encrypt Session' to be 'Yes'.
• Update the edge-node to the eve image w/ this patch
  • use the latest Edgeview container for the client side, edgeview should work normally
  • use the previous version of Edgeview container for the client side, it should get the message from the remote
  • Edgeview encrypted message missing or invalid IV. Need Edgeview Client version 0.8.8 or higher, and exits.
  • Also, in the edge-node logs, it should say the validation failed

Changelog notes

migrate message encryption to AEAD (AES‑GCM) + HKDF

PR Backports

• 16.0-stable

Checklist

• I've provided a proper description
• I've added the proper documentation
• I've tested my PR on amd64 device
• I've tested my PR on arm64 device
• I've written the test verification instructions
• I've set the proper labels to this PR

For backport PRs (remove it if it's not a backport):

• I've added a reference link to the original PR
• PR's title follows the template

And the last but not least:

• I've checked the boxes above, or I've provided a good reason why I didn't
  check them.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 28.08%. Comparing base (2281599) to head (c5b5f4b).
⚠️ Report is 182 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5530      +/-   ##
==========================================
+ Coverage   19.52%   28.08%   +8.55%     
==========================================
  Files          19       19              
  Lines        3021     2314     -707     
==========================================
+ Hits          590      650      +60     
+ Misses       2310     1520     -790     
- Partials      121      144      +23     

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[shjala]

I'm not sure why we don't want to depend on golang.org/x/crypto/hkdf ?

[naiming-zededa]

updated w/ the golang.org/x/crypto/hkdf library, please review.