Remove all references to QAccessible:: {Child|Ancestor|Sibling}

Remove all references to QAccessible:: {Child|Ancestor|Sibling}

These are deprecated in favor of
QAccessibleInterface::child() and QAccessibleInterface::parent()

QAccessible::Sibling can be done with a combination of those two.
This is handled by the bridges, if required.

Change-Id: I2e2a6eb2a982e7c9001a393d69f0c5f1ae9c0970
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@nokia.com>