Reworked preprocess logic and namespace
requested to merge issue/layout_paragraphs-3223849:preprocess/3223849-provide_layout_info into 2.0.x
Reworked preprocess logic to use LP domain classes instead of Paragraph behavior functions. Changed namespace from $variables['layout'] to $variables['layout_paragraphs']. Fixed incorrect return-type document documentation from LayoutParagraphsLayout::getComponent().