feat(module:autocomplete): add autocomplete component

[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
[ ] 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

[coveralls]

Coverage remained the same at 98.077% when pulling c701d29 on HsuanXyz:add-autocomplete into 48d593d on NG-ZORRO:0.7.0.

[codecov]

Codecov Report

Merging #1093 into 0.7.0 will decrease coverage by 0.04%.
The diff coverage is 96.58%.

@@            Coverage Diff            @@
##           0.7.0    #1093      +/-   ##
=========================================
- Coverage     98%   97.95%   -0.05%     
=========================================
  Files        156      153       -3     
  Lines       5451     5772     +321     
  Branches     657      705      +48     
=========================================
+ Hits        5342     5654     +312     
- Misses         0        2       +2     
- Partials     109      116       +7

Impacted Files	Coverage Δ
...uto-complete/nz-autocomplete-optgroup.component.ts	100% <100%> (ø)
components/auto-complete/index.ts	100% <100%> (ø)
components/auto-complete/nz-autocomplete.module.ts	100% <100%> (ø)
components/auto-complete/public-api.ts	100% <100%> (ø)
.../auto-complete/nz-autocomplete-option.component.ts	95.55% <95.55%> (ø)
...ponents/auto-complete/nz-autocomplete.component.ts	96.38% <96.38%> (ø)
...auto-complete/nz-autocomplete-trigger.directive.ts	96.47% <96.47%> (ø)
components/list/nz-list.component.ts	100% <0%> (ø)	⬆️
components/list/nz-list-item-meta.component.ts	100% <0%> (ø)	⬆️
components/modal/nz-modal.component.ts	96.07% <0%> (ø)	⬆️
... and 24 more

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