These schema files are currently generated at build time by
collecting various TUPLE-TREE-YAML comments using the
`extract_yaml.py` script. In this commit we move them to the codebase
but we don't use them yet, this will be done at a later commit for
the sake of readability.
Model classes are now described by a YAML document, which is used to
generate C++ headers containing classes and all the boilerplate
required for YAML serialization/deserialization, usage in
SortedVectors, etc. See the README in include/revng/Model for more
info.
Khaled Ismaeel