feat(module:input-number): add nzBlur & nzFocus property

[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: #396

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[X] No

Other information

如果像 nz-input 一样处理的话，当点击上下按钮时会出发多余的事件，因此我做了一些必要处理。

[coveralls]

Coverage increased (+0.03%) to 41.306% when pulling 3ae30ac on HsuanXyz:feat-number-input into 802a98c on NG-ZORRO:master.

[tigercosmos]

just change the necessary part

[tigercosmos]

Beside the code you add, why did you shift the code?
It seems no need to do this.

[hsuanxyz]

I just want output property to be adjacent.

[LinboLen]

I remember angular team have provided model change on blur

angular/angular#18594