[#157] move structs module to sub crate.

Impl Position for WebWindow.
3 jobs for window-refactoring in 7 minutes and 36 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #12251
build:linux

00:03:47

passed #12252
build:redox

00:04:11

 
  Test
passed #12253
test:linux

00:03:24