wayland: implement fractional scaling

[mahkoh]

See the discussion in https://github.com/JetBrains/JetBrainsRuntime/pull/384

Issues corresponding to the initial commits:

• https://youtrack.jetbrains.com/issue/JBR-7202/wayland-memory-leak-when-resizing-windows
• https://youtrack.jetbrains.com/issue/JBR-7203/wayland-window-is-corrupted-during-resize
• https://youtrack.jetbrains.com/issue/JBR-7198
• https://youtrack.jetbrains.com/issue/JBR-7204/wayland-window-contents-jump-around-at-1.5-scale

[mkartashev]

Let's wait with the fractional scaling until after all the other issues have been resolved.