docs(module:image): add NzImageModule import guide

[stygian-desolator]

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

#6259

What is the new behavior?

Does this PR introduce a breaking change?

• Yes
• No

Other information

[zorro-bot]

This preview will be available after the AzureCI is passed.

[codecov]

Codecov Report

Merging #6291 (f82fa8d) into master (0694079) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #6291      +/-   ##
==========================================
- Coverage   89.80%   89.79%   -0.02%     
==========================================
  Files         477      478       +1     
  Lines       15186    15229      +43     
  Branches     2298     2311      +13     
==========================================
+ Hits        13638    13675      +37     
+ Misses        949      947       -2     
- Partials      599      607       +8     

Impacted Files	Coverage Δ
components/core/util/text-measure.ts	89.56% <0.00%> (-1.74%)	⬇️
components/time-picker/time-holder.ts	94.73% <0.00%> (-1.06%)	⬇️
components/tabs/tab-nav-bar.component.ts	81.69% <0.00%> (-0.71%)	⬇️
components/collapse/collapse.module.ts	100.00% <0.00%> (ø)
components/image/utils.ts	89.65% <0.00%> (ø)
components/collapse/collapse-panel.component.ts	93.10% <0.00%> (+0.24%)	⬆️
components/image/image-preview.component.ts	90.13% <0.00%> (+2.27%)	⬆️
...onents/table/src/addon/filter-trigger.component.ts	38.88% <0.00%> (+3.59%)	⬆️

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