feat(comp: core): add component portal

[LaamGinghong]

fix #113

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• Docs and demo have been added/updated or not needed

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What kind of change does this PR introduce?

• Bugfix
• Feature
• Component style update
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
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• Documentation content changes
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[codecov]

Codecov Report

Merging #178 (c9337b4) into main (b6d178c) will increase coverage by 0.05%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #178      +/-   ##
==========================================
+ Coverage   95.88%   95.94%   +0.05%     
==========================================
  Files          74       76       +2     
  Lines        1557     1580      +23     
  Branches      265      267       +2     
==========================================
+ Hits         1493     1516      +23     
  Misses         33       33              
  Partials       31       31              

Impacted Files	Coverage Δ
packages/cdk/portal/src/Portal.vue	100.00% <100.00%> (ø)
packages/cdk/portal/src/useContainer.ts	100.00% <100.00%> (ø)

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[LaamGinghong]

是不是确定把这个组件挪到cdk？

[danranVm]

丢到 cdk 里面吧。

[LaamGinghong]

重新review

[danranVm]

移到 cdk 的话，要补个简单的文档和 demo ，不然 start 会报错。

[LaamGinghong]

顺便改了一下之前的文档

[danranVm]

LGTM.

[danranVm]

LGTM.