feat(jwt): add local JWKS support for token validation

[zhaohuabing]

This PR allows using an inline string or a ConfigMap to specify the JWKS for token validation in the JWT section of a SecurityPolicy.

implements: #2419

Release note: yes.

[codecov]

Codecov Report

Attention: Patch coverage is 62.50000% with 60 lines in your changes missing coverage. Please review.

Project coverage is 65.20%. Comparing base (40fc25d) to head (1299782).
Report is 10 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/provider/kubernetes/controller.go	0.00%	19 Missing ⚠️
internal/provider/kubernetes/indexers.go	9.52%	18 Missing and 1 partial ⚠️
internal/gatewayapi/securitypolicy.go	84.21%	7 Missing and 2 partials ⚠️
internal/provider/kubernetes/predicates.go	36.36%	5 Missing and 2 partials ⚠️
internal/xds/translator/jwt.go	88.46%	4 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5670      +/-   ##
==========================================
- Coverage   65.21%   65.20%   -0.02%     
==========================================
  Files         214      214              
  Lines       34321    34426     +105     
==========================================
+ Hits        22384    22446      +62     
- Misses      10584    10626      +42     
- Partials     1353     1354       +1     

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[arkodg]

LGTM thanks !