Icon: Add background theme colors

[interactivellama]

Props proposal:
backgroundThemeColor="marketing"

would do the following, but without the style tag:

		<Icon
			assistiveText={{
				label: 'Account',
			}}
			category="standard"
			name="home"
			style={{
				backgroundColor: '#ea7600'
			}}
			title="This is a title"
		/>

Add all cloud themes:

• Global Setup #2A739E - (all clouds)
• Service Cloud
  R127 G36 B67 Web 7f2443
  C37 M96 Y45 K27 Pantone 216C
• Industry Cloud
  R76 G34 B72 Web 4c2248
  C65 M95 Y9 K40 Pantone 519C
• Sales Cloud
  R0 G133 B125 Web 00857d
  C96 M0 Y47 K19 Pantone 7717C
• Commerce Cloud
  R65 G105 B61 Web 41693d
  C71 M8 Y90 K50 Pantone 7743C
• Community Cloud
  R231 G165 B54 Web ffc20e
  C0 M33 Y92 K2 Pantone 2007C
• Marketing Cloud
  R234 G118 B0 Web ea7600
  C4 M65 Y100 K5 Pantone 716C
• Quip
  R207 G69 B29 Web cf451d
  C0 M81 Y100 K0 Pantone 173C

[pulkonet]

I will take this

[interactivellama]

@kevinparkerson Could you groom this spec a little more?

[kevinparkerson]

@pulkonet here is what we'd like for you to do with this issue:

• Create a new folder beneath design-system-react/utilities/ called "product-tokens"
• Add a file to the product-tokens folder called "icon-backgrounds.js"
• Export a single object from icon-backgrounds.js with keys being tied to cloud names (ex: "marketing-cloud") and values being tied to rgba color strings. Use design-system-react/utilities/design-tokens/dist/components.common.js as an example
• Add a productTheme property to the Icon component. Acceptable values should be "global-setup", "service-cloud", "industry-cloud", "sales-cloud", "commerce-cloud", "community-cloud", "marketing-cloud", and "quip"
• Have the Icon component import the icon-backgrounds.js object to apply styles based on productTheme value (you should only need to apply backgroundColor currently as fill is handled by the inverse Icon prop)
• Create an example that shows all productTheme Icon variants
• Make sure to add a note to the productTheme property comment that mentions it is only compatible with an Icon category property value of "standard"