feat(module:select): support open and close panel via keyboard

[wzhudev]

close #1909

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: #1909

What is the new behavior?

User can open and close select panel when select component has focus.

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

Other components may lack of this feature. Maybe we should go through these in next refactor.

[codecov]

Codecov Report

Merging #2038 into master will increase coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #2038      +/-   ##
==========================================
+ Coverage   96.01%   96.03%   +0.01%     
==========================================
  Files         470      470              
  Lines       11424    11437      +13     
  Branches     1515     1519       +4     
==========================================
+ Hits        10969    10983      +14     
  Misses        131      131              
+ Partials      324      323       -1

Impacted Files	Coverage Δ
components/select/nz-select.component.ts	96.75% <100%> (+0.2%)	⬆️
components/select/nz-option-container.component.ts	92.45% <0%> (+0.62%)	⬆️

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