Check group id, metric name, and group name uniqueness

[lquerel]

This PR detects duplications in the following semconv concepts:

• Group ID
• Metric name
• Group name (e.g., resource and event names)

Since there are existing duplications in the current registries (see the example below), we return warnings instead of errors. As usual, the --future flag must be used for future versions of the registry.

Example: https://github.com/search?q=repo%3Aopen-telemetry%2Fsemantic-conventions+path%3A%2F%5Emodel%5C%2F%2F+feature_flag&type=code

For now, the group name duplication detection is disabled.

Closes #306

[jsuereth]

@lquerel I think this is unblocked now if you can update the branch

[codecov]

Codecov Report

Attention: Patch coverage is 85.00000% with 12 lines in your changes missing coverage. Please review.

Project coverage is 73.0%. Comparing base (cab3125) to head (13d5421).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/weaver_diff/src/lib.rs	81.3%	11 Missing ⚠️
crates/weaver_resolver/src/registry.rs	95.2%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #382     +/-   ##
=======================================
+ Coverage   72.5%   73.0%   +0.4%     
=======================================
  Files         49      49             
  Lines       3635    3711     +76     
=======================================
+ Hits        2639    2710     +71     
- Misses       996    1001      +5     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

---

🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests

[jsuereth]

Nit: You can use itertools to .unique this when collector instead of forcing a hashset.

I think performance wise it's the same, just easier to read.