feat(module: grid): support custom icon and local assets

[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
[ ] No

Other information

[codecov]

Codecov Report

Merging #257 into master will decrease coverage by <.01%.
The diff coverage is 55.55%.

@@            Coverage Diff             @@
##           master     #257      +/-   ##
==========================================
- Coverage   86.78%   86.77%   -0.01%     
==========================================
  Files         229      229              
  Lines        7353     7356       +3     
  Branches     1038     1040       +2     
==========================================
+ Hits         6381     6383       +2     
- Misses        567      568       +1     
  Partials      405      405

Impacted Files	Coverage Δ
components/grid/grid.module.ts	100% <100%> (ø)	⬆️
components/grid/grid.component.ts	88.75% <50%> (-1%)	⬇️

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