Remove applets/22/computer

Summary:
BUG: 410854

It's also unnecessary because it's just a symlink to another 22px icon with the same exact name.

Reviewers: VDG, ngraham

Reviewed By: VDG, ngraham

Subscribers: ngraham, kde-frameworks-devel

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D23444