Change VLC icon to be more like official VLC icons

Summary:
This new icon is more in line with our policy on preserving the branding of apps.

I deleted the 22 and 32 px vlc icons because they're not required, they use the old style and this new icon scales down pretty well.

Test Plan:

Reviewers: VDG

Subscribers: kde-frameworks-devel

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D26920