feat: user-agent header is added by default for gRPC and Rest

[karel-rehor]

Closes #

Proposed Changes

• Add an Identity class for collecting information related to the identity of the client
• Update user-agent of rest client to form influxdb3-java:<release>
• Add a default user-agent metadata entry for FlightSQLClient

Checklist

• CHANGELOG.md updated
• Rebased/mergeable
• A test has been added if appropriate
• Tests pass
• Commit messages are conventional
• Sign CLA (if not already signed)

[codecov]

Codecov Report

Attention: Patch coverage is 71.42857% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 88.59%. Comparing base (24ff5e5) to head (2487db0).

Files	Patch %	Lines
...java/com/influxdb/v3/client/internal/Identity.java	50.00%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #133      +/-   ##
==========================================
+ Coverage   88.53%   88.59%   +0.05%     
==========================================
  Files          15       16       +1     
  Lines         855      859       +4     
  Branches      129      129              
==========================================
+ Hits          757      761       +4     
  Misses         42       42              
  Partials       56       56              

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[bednar]

Thanks for your PR 👍 There is only one requirement:

[bednar]

LGTM 🚀