Resource wrapper widget

[maier49]

Type: bug

The following has been addressed in the PR:

• There is a related issue
• All code matches the style guide
• Unit tests are included in the PR
• For new widgets, an entry has been added to the .dojorc
• For new widgets, theme.variant() is added to the root domnode
• Any widget variant uses theme.compose like this
• WidgetProperties are exported

Description:
Adds a Resource widget which is intended to be used only as a custom element to wrap widgets that expect a resource. It can be seen in action here wrapping a list component:
https://resource-widget.vercel.app/

The changes to other widgets were needed because when rendering as a custom element the child widget renders once before the parent can edit its properties, which was accessing an undefined object in widgets that use a resource.
Resolves #1481

[vercel]

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🔍 Inspect: https://vercel.com/dojo/dojowidgets/h1rru3bky
✅ Preview: https://dojowidgets-git-fork-maier49-resource-wrapper.dojo1.vercel.app

[codecov]

Codecov Report

Merging #1494 into master will decrease coverage by 0.13%.
The diff coverage is 62.16%.

@@            Coverage Diff             @@
##           master    #1494      +/-   ##
==========================================
- Coverage   91.06%   90.93%   -0.14%     
==========================================
  Files          84       85       +1     
  Lines        4242     4278      +36     
  Branches     1145     1153       +8     
==========================================
+ Hits         3863     3890      +27     
- Misses        180      184       +4     
- Partials      199      204       +5     

Impacted Files	Coverage Δ
src/chip-typeahead/index.tsx	92.04% <25.00%> (-2.08%)	⬇️
src/list/index.tsx	88.28% <25.00%> (-0.70%)	⬇️
src/select/index.tsx	84.90% <25.00%> (-1.51%)	⬇️
src/typeahead/index.tsx	87.03% <25.00%> (-1.02%)	⬇️
src/resource/index.tsx	90.47% <90.47%> (ø)
src/range-slider/index.tsx	78.35% <0.00%> (+1.75%)	⬆️

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[matt-gadd]

@maier49 this seems a bit intrusive on widget authoring. I couldn't really tell how a user would pass a resource template from html either? is this something we can potentially solve at the framework/element wrapper level without a wrapping widget?

[maier49]

Closing in favor of attempting to resolve this directly in framework
dojo/framework#815