Package design-icewm-themes: Information

- removed themes that included to the main package, this themes Helix,
  Infadel2, Natural are now provided in a package icewm-themes
- fixed license to GPL-2.0

- fixed and restored dropped themes
- added several new themes from http://box-look.org

- dropped a bunch of themes exposing bugs with icewm-1.3 (closes: #28733)
- fixed permissions in the archive
- spec cleanup