* Add missing header files to pythoncore.
* Add missing file filters ("Resource Files" in particular) to
all projects.
* Add new sub-filters for private headers in pythoncore and
for 3rd party source files.
* Add missing _zoneinfo configurations in pcbuild.sln.
* Update bdist_wininst with the new zlib location.
Co-authored-by: Nikita Nemkin <nikita@nemkin.ru>