Support svrx-plugin-ui

[xuchaoying]

Please check if the PR fulfills these requirements

• The commit message follows our guidelines
• Tests is needed?
  • Tests for the changes have been added
• Docs is needed?
  • Docs have been added / updated

What kind of change does this PR introduce?

• Bug fix
• Feature
• Enhencement
• Refactor
• Documents
• Others

1. Add some internal methods for ui
2. Refactor some builtin config schema
3. Support hotreload for some builtin configs
   1. Support plugin reload

What is the related issue?

Does this PR introduce a breaking change?

• breaking change？

Other information:

[codecov]

Codecov Report

Merging #168 into master will increase coverage by 0.26%.
The diff coverage is 96.77%.

@@            Coverage Diff             @@
##           master     #168      +/-   ##
==========================================
+ Coverage    95.7%   95.97%   +0.26%     
==========================================
  Files          49       50       +1     
  Lines        1676     1688      +12     
==========================================
+ Hits         1604     1620      +16     
+ Misses         72       68       -4

Impacted Files	Coverage Δ
packages/svrx/lib/config-list.js	100% <ø> (ø)	⬆️
packages/svrx/lib/constant.js	100% <ø> (ø)	⬆️
...ackages/svrx/lib/plugin/svrx-plugin-serve/index.js	97.36% <100%> (+10.41%)	⬆️
packages/svrx/lib/configure/plugin.js	100% <100%> (ø)	⬆️
packages/svrx/lib/plugin/system.js	90.82% <100%> (ø)	⬆️
packages/svrx/lib/configure/index.js	98.78% <100%> (+0.03%)	⬆️
packages/svrx/lib/svrx.js	95.28% <100%> (+0.18%)	⬆️
...b/plugin/svrx-plugin-history-api-fallback/index.js	88.88% <88.88%> (ø)

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