[config] Decouple config reader and remove config package

[Alanxtl]

Description

Closing #3396 #3204 #2741

!! BREAKING CHANGE: Although dubbo-go does not use config internally any more, downstream users can use it directly. This will make it usable.

Checklist

• I confirm the target branch is develop
• Code has passed local testing
• I have added tests that prove my fix is effective or that my feature works

[Alanxtl]

@Snow-kal @CAICAIIs help review this

[codecov-commenter]

Codecov Report

❌ Patch coverage is 33.33333% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 53.56%. Comparing base (60d1c2a) to head (62c832d).
⚠️ Report is 855 commits behind head on develop.

Files with missing lines	Patch %	Lines
common/extension/config_reader.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3449      +/-   ##
===========================================
+ Coverage    46.76%   53.56%   +6.79%     
===========================================
  Files          295      460     +165     
  Lines        17172    35182   +18010     
===========================================
+ Hits          8031    18846   +10815     
- Misses        8287    14856    +6569     
- Partials       854     1480     +626     

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[Alanxtl]

ci fail 因为 dubbo-go-sample 依然依赖 config 已提pr修复 apache/dubbo-go-samples#1113

[CAICAIIs]

lgtm, cool work

[Alanxtl]

CI already pass

[Snow-kal]

lgtm ♡

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
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