Popover component

[LHinson]

Popover component from here: https://pf-next.com/components/Popover/examples/

See notes below about leveraging popper.js. This issue also includes identifying the best approach for a wrapper and utilizing core CSS.

Note re: behavior, ensure that popover only closes when the user clicks either the close icon or outside of the popover itself as there are use cases where a user needs to be able to select text from the popover body.

[jschuler]

We've identified the following thirdparty to use for the tooltip and popover components:

popper.js - Positioning engine
To use it we need a react wrapper. We can create or own or use ready-made libraries.

Examples from other projects that have created their own:
material-ui
reactstrap
gist example

Examples for react components that have already done so:
Tooltip
react-tippy
react-popper-tooltip
react-tooltip
Popover
react-popper

Note: To keep bundle sizes down, we shouldn't require the consumer to have these thirdparty libraries loaded in if they are not using tooltip/popover components.