Weaver Policy Engine

[lquerel]

This PR is based the proposal #81.

This initial implementation (based on the regorus policy engine) allows for the detection of violations against best practices within a semantic convention registry (before the resolution phase) through one or several policy files (in rego format). A future PR will enable the application of policies after the registry's resolution to detect other types of violations.

A detailed description of the operating principle can be found in the README.md of the weaver_policy_engine crate.

The impact on performance from evaluating policies on all files in the registry is imperceptible.

Future developments:

• Allow the application of policies after the registry resolution phase.
• Enable specifying two versions of the same registry to apply policies comparing the schema evolution of groups, attributes, or any other signals.
• Currently, only the weaver registry check command has the capability to apply these policies. Support for other commands will be added in future PRs.

Note: Due to a conflict issue with serde_json, this PR references a fork of the regorus project. A description of the problem can be found here. The described issue is not a major problem, and I believe it is temporary.

[codecov]

Codecov Report

Attention: Patch coverage is 75.86207% with 21 lines in your changes are missing coverage. Please review.

Project coverage is 63.6%. Comparing base (acf6fd0) to head (a5ca1d2).

Files	Patch %	Lines
crates/weaver_checker/src/lib.rs	76.3%	9 Missing ⚠️
crates/weaver_resolver/src/lib.rs	73.5%	9 Missing ⚠️
crates/weaver_semconv_gen/src/lib.rs	40.0%	3 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main     #87   +/-   ##
=====================================
  Coverage   63.6%   63.6%           
=====================================
  Files         54      56    +2     
  Lines       3245    3282   +37     
=====================================
+ Hits        2065    2089   +24     
- Misses      1180    1193   +13     

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[jsuereth]

Wow, that was a lot more tearing things apart than I expected, but I think this separation will pay off later!

Thanks for adding this, excited to try it out/expand on it!