Use light theme for printSpooler

- replace png's by vector graphics
- Use alredy existing icons if possible
- Remove unnnecessary hard coded color values
- hard code all colors for preview-page as the background colors are
  hard coded, hence foreground also needs to be hard coded.
- Unify layout of loading/error/select printer UI

Test: Looked at print spooler. Switched theme to dark and checked if all
      looks ok too.
Change-Id: I07cc619d575c7372bd18550db8f2582df657cc5c