refactor(module:card): refactor card

[vthinkxie]

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?

Issue Number: N/A

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[ ] No

Other information

[codecov]

Codecov Report

Merging #4778 into master will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4778      +/-   ##
==========================================
- Coverage   93.25%   93.24%   -0.01%     
==========================================
  Files         505      505              
  Lines       12734    12736       +2     
  Branches     1957     1957              
==========================================
+ Hits        11875    11876       +1     
- Misses        447      449       +2     
+ Partials      412      411       -1     

Impacted Files	Coverage Δ
components/card/card-meta.component.ts	100.00% <0.00%> (ø)
components/card/card-loading.component.ts	100.00% <0.00%> (ø)
components/card/card.component.ts	90.90% <0.00%> (ø)
components/time-picker/time-holder.ts	97.31% <0.00%> (+0.67%)	⬆️

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