Moved global methods, new features for focus restore and boundary directions

Added

• New property for useFocusable - focusBoundaryDirections, array of directions to block when isFocusBoundary is enabled
• New property useFocusable - forceFocus to mark the component to be the target for auto-restore focus logic when focus is lost
• New global method doesFocusableExist to check if the focusable component exists before setting focus on it. Safety feature

Changed

• [BREAKING] Top level exports setFocus, getCurrentFocusKey, navigateByDirection, pause, resume, updateAllLayouts are now exported from SpatialNavigation instead of useFocusable hook.

Fixed

• Context display name is now called FocusContext in React Devtools
• Updating lastFocusedChildKey for newly added parent components