Add Ice Cold wallpaper

Summary:
Per tradition, we add the previous Plasma version's wallpaper to this repo when it gets
replaced with a new one in Breeze, as is being done in D26953.

Depends on D26953

Test Plan:
Apply and deploy patch
Right-click on Desktop > Configure
See Ice Cold in the list

Reviewers: VDG, Plasma, davidedmundson

Reviewed By: Plasma, davidedmundson

Subscribers: plasma-devel

Tags: Plasma

Differential Revision: https://phabricator.kde.org/D26954