Serde is now a non-optional dependency

[cberkhoff]

Removed the enable-serde flag and made Serde a non-optional dependency. Removed the cfg attributes that depended on the feature since now the library is included by default.

Testing

Both unit tests and ./pre-commit pass.

closes #588

[codecov]

Codecov Report

Attention: Patch coverage is 58.33333% with 10 lines in your changes are missing coverage. Please review.

Project coverage is 90.01%. Comparing base (fc791b2) to head (21a08b2).

Files	Patch %	Lines
ipa-core/src/bin/ipa_bench/models.rs	0.00%	5 Missing ⚠️
ipa-core/src/cli/noise.rs	0.00%	2 Missing ⚠️
ipa-core/src/helpers/mod.rs	75.00%	1 Missing ⚠️
ipa-core/src/protocol/mod.rs	50.00%	1 Missing ⚠️
ipa-core/src/protocol/step/compact.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #996      +/-   ##
==========================================
+ Coverage   89.71%   90.01%   +0.30%     
==========================================
  Files         169      168       -1     
  Lines       23029    22959      -70     
==========================================
+ Hits        20660    20667       +7     
+ Misses       2369     2292      -77     

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[akoshelev]

lgtm, thanks! The code coverage issues are probably coming from us not using these structs at all. Would you be able to test which ones are needed by simply deleting them and compiling the code? We may be able to clean up even more things

[cberkhoff]

I went over the classes that were flagged as part of the coverage check and they were either:
a) Not used anywhere in the code. I removed those classes in the last commits.
b) Tests where not exercising the classes for which I added serialization/deserialization. This issue is orthogonal to this PR and rather tackle that separately.

[akoshelev]

lgtm, will merge it tomorrow