doc: make it clear when DT properties are deprecated

Devicetree properties may be deprecated. Make deprecated properties
more prominent in the generated bindings documentation as follows:

  1. For deprecated node-specific properties, make a new tab which
     only contains the deprecated properties

  2. For deprecated child-binding properties, ensure a line
     mentioning derpecation is in the property details

  3. For deprecated 'base' binding properties, do the same thing as
     child-bindings. Note that there aren't any such properties,
     but they'd fall in this bucket if we add any later on.

Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>