Remove obsolete pattern icons

This is the first batch of icon artwork clean-up. 
The main criteria for removal was that icons are not used by any yast package available under repos in https://github.com/yast/ (all repos have been grepped). 
I did no research whether the icons are used by other packages outside this scope, but practically only maintained yast packages should be given access to this files.
If you think there is someone who should get noticed about this clean-up, please let me/him know.