bpo-34977: Add Windows App Store package (GH-11027)

Also adds the PC/layout script for generating layouts on Windows.

PC/layout/support/catalog.py

@@ -0,0 +1,44 @@
+"""
+File generation for catalog signing non-binary contents.
+"""
+
+__author__ = "Steve Dower <steve.dower@python.org>"
+__version__ = "3.8"
+
+
+import sys
+
+__all__ = ["PYTHON_CAT_NAME", "PYTHON_CDF_NAME"]
+
+
+def public(f):
+    __all__.append(f.__name__)
+    return f
+
+
+PYTHON_CAT_NAME = "python.cat"
+PYTHON_CDF_NAME = "python.cdf"
+
+
+CATALOG_TEMPLATE = r"""[CatalogHeader]
+Name={target.stem}.cat
+ResultDir={target.parent}
+PublicVersion=1
+CatalogVersion=2
+HashAlgorithms=SHA256
+PageHashes=false
+EncodingType=
+
+[CatalogFiles]
+"""
+
+
+def can_sign(file):
+    return file.is_file() and file.stat().st_size
+
+
+@public
+def write_catalog(target, files):
+    with target.open("w", encoding="utf-8") as cat:
+        cat.write(CATALOG_TEMPLATE.format(target=target))
+        cat.writelines("<HASH>{}={}\n".format(n, f) for n, f in files if can_sign(f))