YangInstanceIdentifier builder: allow adding PathArgument nodes

Adding pre-constructed PathArguments onto a builder can be useful, as it allows us to share object instances with other code.

Instantiating a builder is advantegeous when we want to pre-construct a YangInstanceIdentifier for reuse.

Right now I have to do the following:
newTablesRoot = YangInstanceIdentifier.builder(newPeerPath.node(EMPTY_ADJRIBIN.getIdentifier()).node(TABLES)).build();

Where I should be able to do the following:

newTablesRoot = YangInstanceIdentifier.builder(newPeerPath).node(EMPTY_ADJRIBIN.getIdentifier()).node(TABLES).build();

Which is more efficient.