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.

include CHANGELOG.rst
include INSTALL.rst
include LICENSE.rst
include README.rst

include pytest.ini
include setup.cfg
include requirements.txt
include dev-requirements.txt

recursive-include piecrust *
recursive-include tests *

global-exclude *.py[cdo] __pycache__ *.so
global-exclude .DS_Store Thumbs.db Desktop.ini
global-exclude *.swp *~ *.bak