This reverts commit 49f6abb.
49f6abb includes a lot of unintendet reverts from f604468 (Update Japanese holidays)
In follwing thread on KDE Bugzilla, Allen Winter seems to have merged very old code.
https://bugs.kde.org/show_bug.cgi?id=365241
As a result, some updates I made in https://phabricator.kde.org/D5736 is reverted.