Clean up use of menuAppendTo props on relevant components

[nicolethoen]

By default, menuAppendTo should append 'inline' so that menus or poppers are always append to the trigger, in a popper, with absolute positioning so that the menus overlay the content below it.

Currently, selecting 'inline' for some components places the menu or other content after the trigger with static positioning so that it does not overlay the content below it. That should not be the case.

Also, once all menu like components are rebuilt to be constructed composably, they should not need a wrapper div by default, and the popper should be appended to the trigger 'inline' by default.

Work that needs to be done:

• Date picker: needs appendTo='inline' by default #8596
• Label group: 'Editable labels with add dropdown' should append the popper to the label by updating Popper's appendTo={toggleRef.current} ( #8597
• Nav: flyout menus should be appended inline - not the the end of the document body. This would be configured in the Popper component declared as NavItem's flyoutPopper. #8598
• Popover's appendTo prop defaults to the document body. it should default to inline. #8599
• Composable menu demos should append Popper inline by default #8600

[tlabaj]

all task have been completed