feat(module:modal): feat add modal closable and maskClosable demo

[Guoyuanqiang]

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?

[ ] Yes
[x] No

Other information

[codecov]

Codecov Report

Merging #195 into master will decrease coverage by <.01%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master     #195      +/-   ##
==========================================
- Coverage   86.26%   86.25%   -0.01%     
==========================================
  Files         222      222              
  Lines        7163     7161       -2     
  Branches     1003     1003              
==========================================
- Hits         6179     6177       -2     
  Misses        586      586              
  Partials      398      398

Impacted Files	Coverage Δ
components/modal/modal.component.ts	72.65% <0%> (-0.43%)	⬇️

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