core: Continue PieCrust3 refactor, simplify pages. The asset pipeline is still the only function pipeline at this point. * No more `QualifiedPage`, and several other pieces of code deleted. * Data providers are simpler and more focused. For instance, the page iterator doesn't try to support other types of items. * Route parameters are proper known source metadata to remove the confusion between the two. * Make the baker and pipeline more correctly manage records and record histories. * Add support for record collapsing and deleting stale outputs in the asset pipeline.

from piecrust.serving.server import WsgiServer


def get_app(root_dir, cache_key='prod', enable_debug_info=False):
    app = WsgiServer(root_dir,
                     cache_key=cache_key,
                     enable_debug_info=enable_debug_info)
    return app