feat: add support for all retrievers in cli

[DeamonDev]

Description

I added new flags related to other kind of retrievers. Based on them the new retriever is being spawned (but see #4024).
There is also new --check-mode flag which when present would only dump the configuration of retriever being used to perform evaluate call. It also served me while testing some multi-flags (like http's --header) because there is some kind of parsing logic at evaluate_cmd layer.

The redis retriever is not supported because of #4023. We may of course hack it and provide empty output when -kind=redis but I think the refactor of RetrieverConf struct would benefit more.

Closes issue(s)

Resolve #3876

Checklist

• I have tested this code
• I have added unit test to cover this code
• I have updated the documentation (README.md and /website/docs)
• I have followed the contributing guide

[netlify]

✅ Deploy Preview for go-feature-flag-doc-preview canceled.

Name	Link
🔨 Latest commit	fcf358d
🔍 Latest deploy log	https://app.netlify.com/projects/go-feature-flag-doc-preview/deploys/68e36d81b4b40f0008b3224f

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

❌ Patch coverage is 89.37500% with 17 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.04%. Comparing base (4c730fb) to head (fcf358d).
⚠️ Report is 24 commits behind head on main.

Files with missing lines	Patch %	Lines
cmd/cli/evaluate/evaluate_cmd.go	91.61%	8 Missing and 5 partials ⚠️
retriever/gcstorageretriever/retriever.go	0.00%	2 Missing ⚠️
retriever/s3retrieverv2/retriever.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4025      +/-   ##
==========================================
+ Coverage   83.92%   84.04%   +0.11%     
==========================================
  Files         137      137              
  Lines        6813     6968     +155     
==========================================
+ Hits         5718     5856     +138     
- Misses        884      897      +13     
- Partials      211      215       +4     

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