Feature/wsdev 6699 loader components

[HanqingZhou]

PR Checklist & Notes

What type of PR is this? (check all applicable)

• New component
• New feature
• Refactor
• Bug fix
• Optimization / Build Tools
• Documentation Update

Is this a breaking change?

If yes, please note which project will be impacted.

• Yes
• No

Have you made an entry in the Changelog?

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• Yes
• No

Have you made changes to dependencies?

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• Added
• Updated
• Removed
• Combo of any of the above
• No

QA Instructions, Screenshots, Recordings

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about any UI changes or if a test should be done on a specific browser. Add any other detail relevant to this PR.

UI accessibility concerns?

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accessibility is impacted and tested. If there are no accessibility concerns delete this section.

[HanqingZhou]

Component	Refactor Status	Diff Created	Primary Review	Secondary Review
Loaders	port	Yes	No	No
→ Block Loader	port	prior #458	No	No
→ Button Loader	port	prior #458	No	No
→ Calendar Loader	port	Yes	No	No
→ Card Loader	port	Yes	No	No
→ Description Loader	port	Yes	No	No
→ Event Loader	port	Yes	No	No
→ Form Loader	port	prior #458	No	No
→ Listing Loader	port	Yes	No	No
→ Page Header Loader	port	prior #458	No	No
→ Page Loader	port	prior #458	No	No
→ Pagination Loader	port	Yes	No	No
→ Table Loader	port	prior #458	No	No
→ Top Nav Loader	port	prior #458	No	No

prior #458 = already ported in merged PR #458 ("Refactor/wsdev 5068 section spacing"); not part of this diff.