Improve outside click and focus trap handing of EuiNavDrawer

[ryankeairns]

The one last thing I saw that was odd is that in mobile screen sizes, clicking the white area of the flyout closes the whole sidebar. It doesn't do this in larger breakpoints.

I think there is something a little off with how the OutsideClickDetector is being enabled/disabled by the mobile menu button. This was becoming apparent when I was trying to fix up the 'toggle flyout if you click/touch the same icon again'. As I dug into it, it felt like a thing that would make for a follow-up PR as it touches logic in a few places.

This issue could likely be addressed along with #1713

Originally posted by @ryankeairns in #1701 (comment)

[cchaos]

Edited title since it's an all around problem, not just mobile specific.

[cchaos]

Also including focus trap on this one.

[seeruk]

Not sure if this'll be related to this issue, but there's something odd going on right now in the latest version of EUI where if I lock the NavDrawer, then unlock it, it doesn't detect the outside clicks and close the NavDrawer. Maybe something caused by the TypeScript migration?

Edit: I think I can see the issue actually, will submit a PR.

[cchaos]

This component is being deprecated in favor of EuiCollapsibleNav