feat(module:cascader): support standalone component

[ParsaArvanehPA]

PR Checklist

Please check if your PR fulfills the following requirements:

• [✔] The commit message follows our guidelines: https://github.com/NG-ZORRO/ng-zorro-antd/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• [✔] Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[✔] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Application (the showcase website) / infrastructure changes
[ ] Other... Please describe:

What is the current behavior?

What is the new behavior?

Updated Cascader component to work as a standalone component.

Does this PR introduce a breaking change?

[ ] Yes
[✔] No

Other information

[zorro-bot]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (165f171) 91.71% compared to head (42a89b2) 91.71%.
Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #8271   +/-   ##
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  Coverage   91.71%   91.71%           
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  Files         518      518           
  Lines       17887    17887           
  Branches     2837     2837           
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  Hits        16405    16405           
  Misses       1181     1181           
  Partials      301      301           

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[Nicoss54]

LGTM