Builds all nodes below the top-level <sitemap> element, and returns the
<pipelines> node. There is no node for >sitemap< since no processing
occurs at this level.
buildNode(Configuration config)
Build the ProcessingNode and its children from the given
Configuration, and optionnaly register it in the tree builder
for lookup by other LinkedProcessingNodeBuilders.
Build the ProcessingNode and its children from the given
Configuration, and optionnaly register it in the tree builder
for lookup by other LinkedProcessingNodeBuilders.