Implement Segmented Control component

[jmuzina]

Vanilla's segmented control component is not currently implemented in React Components. Implementing it in RC will prevent teams from needing to separately implement it.

[jmuzina]

WPE has our own React implementation of segmented control, in use on the 360 results page. This could be a good candidate for upstreaming

(cc @vitorhpassos @jademathre-canonical @jpmartinspt - I noticed this in Vitor's PR extending keyboard functionality of our segmented control. We could ship this improvement to the rest of the web team :) )

[edlerd]

I agree this component would be nice to add! LXD has a couple of usages for the segmented control, but no dedicated component. Most usages use this pattern:

        <div className="p-segmented-control">
          <div className="p-segmented-control__list">{menuElements}</div>
        </div>

Adding a custom class name would be a nice feature too.