feat: support hash key option in loadbalance

[welkeyever]

What type of PR is this?

feat

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feat: 在负载均衡中支持 hashkey 选项

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en: Add support for custom hash key configuration in load balancing. Users can now specify a custom hash key option when using consistent hash load balancing algorithm, providing more flexibility for routing decisions based on specific request parameters.
zh(optional):

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[codecov]

Codecov Report

❌ Patch coverage is 50.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.37%. Comparing base (09515f8) to head (497e60f).

Files with missing lines	Patch %	Lines
pkg/app/client/loadbalance/lbcache.go	50.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1471      +/-   ##
===========================================
- Coverage    86.38%   86.37%   -0.01%     
===========================================
  Files          149      149              
  Lines        14429    14432       +3     
===========================================
+ Hits         12464    12466       +2     
- Misses        1427     1428       +1     
  Partials       538      538              

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