Adds CMAC

[Elvrarin]

Issues:

See SIM P307101963

Description of changes:

Currently, aws-lc-rs only supports HMAC
This commit adds CMAC, with support for AES 128, 192, 256 and TDES keys.
https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38b.pdf

Call-outs:

• Some APIs like Key::new(), sign(), Context::update(), Context::sign() may panic. This is done to be consistent with the API of HMAC
• According to aws-lc's service indicator, AES 192 and TDES aren't FIPS approved. (Question: which fips document?)

Testing:

• Unit tests added.
• Integration Test data is copied from here in aws-lc

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and the ISC license.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 91.13300% with 18 lines in your changes missing coverage. Please review.
✅ Project coverage is 92.34%. Comparing base (c358484) to head (c661b48).
⚠️ Report is 275 commits behind head on main.

Files with missing lines	Patch %	Lines
aws-lc-rs/src/cmac.rs	91.13%	14 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #903      +/-   ##
==========================================
- Coverage   95.80%   92.34%   -3.46%     
==========================================
  Files          61       74      +13     
  Lines        8143     9862    +1719     
  Branches        0     9862    +9862     
==========================================
+ Hits         7801     9107    +1306     
- Misses        342      464     +122     
- Partials        0      291     +291     

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[justsmth]

The truncation used here and in the other functions is not needed -- it would actually hide a bug were we to produce too long of a signature.

[Elvrarin]

I copied these tests data, and test functions from the aws-lc. The original tests also does a truncation. Without the truncation, the tests start to fail.
https://github.com/aws/aws-lc/blob/main/crypto/fipsmodule/cmac/cmac_test.cc#L226-L227

[justsmth]

Ok, we should just trancate it to tlen then -- it should never be longer than the actual tag:

let truncated_sig = &signature.as_ref()[..tlen];