refactor!: Separate Client and Provider metadata, add client creation tests

[maxveldink]

This PR

• Separates the Metadata class into ClientMetadata and ProviderMetadata structs that explicitly call out the required fields.
• Adds tests demonstrating the client creation requirements are met from the spec
• I noticed that we were still pulling in concurrent-ruby but no longer using it for the concurrent Array primitive. Removed that as well

Follow-up Tasks

Move on to testing client flag evaluation testing

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.42%. Comparing base (f8e016f) to head (4f0cb23).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #116      +/-   ##
==========================================
- Coverage   99.44%   99.42%   -0.02%     
==========================================
  Files          13       14       +1     
  Lines         180      174       -6     
==========================================
- Hits          179      173       -6     
  Misses          1        1              

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