Make KSharedDataCache work for Windows

* Makefile.am (EXTRA_DIST): Add it.
* patches/kcoreaddons/0001-Add-KSharedDataCache-for-Windows.patch:
New.

Although it still does way too many stats to find other sizes
of icons.

Upstream MR is:
https://invent.kde.org/frameworks/kcoreaddons/-/merge_requests/339

This helps a bit with icon load times for

• GnuPG-Bug-Id: T4066