Add browser width and height to AxeSession

[kyberorg]

• Exec JS at Session create time
• Monitor browser size changes with Vaadin callback.

[kyberorg]

https://vaadin.com/docs/latest/advanced/browser-access

[kyberorg]

Device
  Screen
    width
    height

Device.hasScreen() - w>0 && h>0
Device.getScreen().getWidth()

DeviceUtils.hasSmallScreen() {
  If (no session) return DeviceUtils.isMobile(); //?
  If (Session.hasScreen) {
     return Session.getScreen().getWidth() <= SMALL_SCREEN_BREAKPOINT;
  } else {
     DeviceUtils.isMobile(); //?
   }
}