Draft NEW Selector component

[taysea]

What does this PR do?

Status: Early draft state for component/API feedback. Selection, accessibility, theming, keyboard logic has not been implemented.

I've left a variety of "TO DO" comments in the code to capture questions I ran into while building.

Use the storybook examples and index.d.ts files to get a feel for developer experience + component behavior.

Introduces new set of "Selector" components:

• SelectorGroup
• Selector
• SelectorHeader
• SelectorBody (Should this be more generic in case people want multiple sections (for example, one with pad, but one full width? "SelectorContent"?)
• SelectorTitle

Component	Styling responsibilities	State/behavior responsibilities	Configurable props
SelectorGroup	Direction and spacing between individual selectors.	Manages selected state, passes down via context	--
Selector	Container styling of individual selector (border, rounding, selected border)	Roving tabIndex	--
SelectorHeader	Padding around content	Renders selection indicator (RadioButton/CheckBox)	title, will render SelectorTitle
SelectorBody	Padding around content	--	--
SelectorTitle	Text style	--	--

For details on the purpose for this component set see: grommet/hpe-design-system#3840

Considerations for how this was built

Based on the 80% case for custom content, it makes most sense to approach this component from a "compositional" mindset, rather than just a "configurable" one.

Where should the reviewer start?

What testing has been done on this PR?

How should this be manually tested?

Do Jest tests follow these best practices?

• screen is used for querying.
• The correct query is used. (Refer to this list of queries)
• asFragment() is used for snapshot testing.

Any background context you want to provide?

What are the relevant issues?

Closes grommet/hpe-design-system#3840

Screenshots (if appropriate)

Do the grommet docs need to be updated?

Should this PR be mentioned in the release notes?

Is this change backwards compatible or is it a breaking change?

[taysea]

Closing this PR as we've decided it doesn't warrant a Grommet component at this time.