Popovers: separate out "focus" trigger and "dismiss on next click" functionality

It feels inappropriate that the use of focus trigger is touted as being the solution to close the popover on next click. If anything, that is basically a side effect of the fact that the popover is set to react to focus/blur.

https://v5.getbootstrap.com/docs/5.0/components/popovers/#dismiss-on-next-click

Making the popover actually open on focus for keyboard users is...unexpected for some, and not really ideal (imagine tabbing through a page with lots of these, and having popovers fired at you all the time when all you want to do is progress past the trigger elements to reach some other part of the page). It shouldn't be pushed as the solution for dismissing on next click.

It would probably make sense to provide a new option for popovers to explicitly say "close this on next click" (and probably, more specifically, next click outside of the popover itself, to be more specific). then, for focus trigger, mention that a side-effect of using that is that popovers close on blur/when the trigger loses focus, and that THIS also happens when clicking somewhere else on the page.

while this has been this way in v4 as well, v5 would give us the option of introducing a bit more separation here.