feat(module: picker): picker ngModel support

[tirelyl]

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-mobile/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?

[x] Yes
[ ] No

Other information

[codecov]

Codecov Report

Merging #165 into master will decrease coverage by 0.13%.
The diff coverage is 93.33%.

@@            Coverage Diff             @@
##           master     #165      +/-   ##
==========================================
- Coverage   86.47%   86.34%   -0.14%     
==========================================
  Files         221      221              
  Lines        7071     7081      +10     
  Branches      989      990       +1     
==========================================
- Hits         6115     6114       -1     
- Misses        561      570       +9     
- Partials      395      397       +2

Impacted Files	Coverage Δ
components/picker/picker-options.provider.ts	100% <ø> (ø)	⬆️
components/picker/picker.component.ts	67.2% <100%> (-5.38%)	⬇️
components/picker/picker.directive.ts	83.95% <92.85%> (+1.09%)	⬆️

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