feat(module:space): add nzSplit support

[hsuanxyz]

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
[x] 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 #6487 (319b0dc) into master (85ea273) will increase coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #6487      +/-   ##
==========================================
+ Coverage   89.82%   89.86%   +0.03%     
==========================================
  Files         478      479       +1     
  Lines       15314    15323       +9     
  Branches     2475     2333     -142     
==========================================
+ Hits        13756    13770      +14     
+ Misses        940      935       -5     
  Partials      618      618              

Impacted Files	Coverage Δ
components/pagination/pagination-item.component.ts	100.00% <ø> (ø)
components/space/space.module.ts	100.00% <ø> (ø)
components/space/space-item.component.ts	100.00% <100.00%> (ø)
components/space/space-item.directive.ts	100.00% <100.00%> (ø)
components/space/space.component.ts	100.00% <100.00%> (ø)
components/tooltip/base.ts	91.98% <100.00%> (+0.94%)	⬆️
...ts/table/src/table/table-inner-scroll.component.ts	81.42% <0.00%> (+4.28%)	⬆️

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