[#157] refactor theme code to move it to

own sub crate.
3 jobs for window-refactoring in 6 minutes and 31 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #12336
build:linux

00:03:18

passed #12337
build:redox

00:03:36

 
  Test
passed #12338
test:linux

00:02:54