feat: enhance remote claim builder: implementation of remote payload claims and trust policy enforcement

[denopink]

• introduce the ability to specify which claims from the remote claims endpoint you want to merge into your jwt claims set (ignoring remote claims that are not specify)
  • the default behavior - if not configured, then all of themis' claims can/will be overwritten by remote payload claims
• introduce the ability to specify which policy is used to determine which turst related claims are sourced from between remote claims and themis.
  • default behavior - themis' trust related claims will always be overwritten by remote claims (if provided)
• implement the actual remote payload claims and trust policy enforcement
• tested this iteration of themis in cd and no regressions were observed in the acceptance or integration tests
• update tests
• update config example

[codecov]

Codecov Report

❌ Patch coverage is 83.67347% with 24 lines in your changes missing coverage. Please review.
✅ Project coverage is 52.93%. Comparing base (a929880) to head (47200cd).

Files with missing lines	Patch %	Lines
token/claimBuilder.go	81.05%	18 Missing ⚠️
main.go	0.00%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #353      +/-   ##
==========================================
+ Coverage   50.32%   52.93%   +2.61%     
==========================================
  Files          55       57       +2     
  Lines        2013     2146     +133     
==========================================
+ Hits         1013     1136     +123     
- Misses        964      977      +13     
+ Partials       36       33       -3     

Flag	Coverage Δ
unittests	52.93% <83.67%> (+2.61%)	⬆️

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