feat: support custom config files

[chemdemo]

Checklist

• npm test passes
• tests are included
• documentation is changed or added
• commit message follows commit guidelines

Description of change

Service类支持传入自定义的配置文件：

new Service({ configFiles: ['.mycustomrc.ts', 'config/mycustomrc.ts'] })

[codecov]

Codecov Report

Merging #6142 (448750e) into master (e46701e) will increase coverage by 0.03%.
The diff coverage is 83.33%.

@@            Coverage Diff             @@
##           master    #6142      +/-   ##
==========================================
+ Coverage   83.20%   83.24%   +0.03%     
==========================================
  Files         158      158              
  Lines        3502     3510       +8     
  Branches      942      946       +4     
==========================================
+ Hits         2914     2922       +8     
  Misses        578      578              
  Partials       10       10              

Impacted Files	Coverage Δ
packages/core/src/Config/Config.ts	62.99% <75.00%> (+1.20%)	⬆️
packages/core/src/Service/Service.ts	96.34% <100.00%> (+0.06%)	⬆️

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[ycjcl868]

文档 API 需要补下

[chemdemo]

api文档已更新。

[ycjcl868]

+1 @sorrycc