Add a whole whack of holiday files derived from the Python holidays project.

That project's repo is at https://github.com/vacanza/holidays

include/holidays/it/fe.rem

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: MIT
+# Holiday file for subdivision FE in Italy
+# Derived from the Python holidays project at
+# https://github.com/vacanza/holidays
+#
+# Note that this file includes only the holidays for
+# the specific subdivision FE.
+#
+# If you want the national holidays as well, you must
+# also include [$SysInclude]/it.rem
+
+OMIT 23 April MSG San Giorgio