Add YaST and new preference icons

Summary:
Add YaST icons and a number of preference icons that will be useful for KDE software in the future.

Change apps/32 to scalable so that the patch can pass the scalable test and add apps/64 to index.theme

Test Plan:
ViewBackground is the background color that will be used in YaST Control Center.

Used by YaST. Most of these are symlinks to the new preference icons.

Not used by YaST, but currently included in the patch.

Reviewers: VDG, cfeck, broulik, elvisangelaccio, ngraham

Reviewed By: VDG, ngraham

Subscribers: rooty, sitter, fvogt, hellcp, ngraham, kde-frameworks-devel

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D17623