Support different kinds of button without variants

[agubler]

Type: feature

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:

This change repurposes the kind property of the Button to define the actual different kinds of button i.e. outlined, text and contained as per the material spec. The existing behaviour for kind in the button has been removed, as the primary and secondary colour are not a "kind". In the future we will look at whether we implement a property to control colour.

kind will be the consistent approach to supporting variants such as outlined, and will update the card and other places to reflect this.

This is a breaking changes as RaisedButton and OutlinedButton no longer exist and the default button style is Contained (aka Raised).

[vercel]

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widget-test-docs – ./

🔍 Inspect: https://vercel.com/dojo/widget-test-docs/7KG6219xseo9uQp3AuRNHAs33HKx
✅ Preview: https://widget-test-docs-git-fork-agubler-proper-kinds-dojo1.vercel.app

dojo.widgets – ./

🔍 Inspect: https://vercel.com/dojo/dojo.widgets/5QDYMw6jSbPjxLb8hE63fyvKFi3M
✅ Preview: https://dojowidgets-git-fork-agubler-proper-kinds-dojo1.vercel.app

[codecov]

Codecov Report

Merging #1751 (4d121b0) into master (d09d090) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1751      +/-   ##
==========================================
- Coverage   90.55%   90.54%   -0.02%     
==========================================
  Files          96       94       -2     
  Lines        5220     5193      -27     
  Branches     1419     1418       -1     
==========================================
- Hits         4727     4702      -25     
  Misses        241      241              
+ Partials      252      250       -2     

Impacted Files	Coverage Δ
src/floating-action-button/index.tsx	100.00% <ø> (ø)
src/accordion/index.tsx	100.00% <100.00%> (ø)
src/button/index.tsx	86.79% <100.00%> (+3.15%)	⬆️

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