Create hooks for Focus Trap and ESC listener and use in Modal, Popover and Tooltip

[lavelle]

Scope of this change:

• Extract out a hook for the ESC handler
• Extract out a hook for focus trapping
• Use them in Popover, Tooltip and ModalCurtain
• Convert ModalCurtain to a function component with hooks in order to allow it to use the new hooks
• Extract out some Tooltip logic into a function component to use the hooks.

Not doing:

• The main Tooltip is still a class – converting it to be a function component should be another PR, since it has a lot of lifecycle hooks and state, and we want to make sure we don't break anything. When we do this, Tooltip can use the hook directly.

• Converting the deprecated ModalStandard and it's underlying ModalBase to use these hooks. These components have their own ESC handling, but it's not worth the effort to rewrite them as function components. We should work on removing uses in website and deleting them.

[danoc]

I'm getting this on Chrome when clicking on the button to open the popover.

Can you either:

1. Remove the outline from the outer container? (Normally I'm against removing outlines, but the outermost element is not actually interactive and when the user hits Tab they'll see a focus state.)
2. Work with Jon to restyle it?

I'd personally prefer the first option but am open the second if you feel strongly.

[lavelle]

removed the outline

[danoc]

Looks great! ✨