Host 3D: prevent Presentation Framework assertion when setting scale factor.

Host 3D: do not upset GUI when it attempts to set scale factor when 3D output not yet initialized. Cache it and restore once output initialized.

3D content scaling: keep window size parameters unchanged (not multiplied by scaling factor); update window geometry once scaling factor updated (fixes visual artifacts when Win guest login screen displayed).

3D: scalling factor: separate scaling factors along X and Y axes; move out from atomic variables to read-write semaphores.

Host 3D: prepare for content scaling.

Revert r96781, r96707 and r96693 since these commits affect 3D overlay window badly on Windows host.

Host 3D: Chromium server: drop non-functional code.

Host 3D: Presentation framework: do not re-create 3D window on framebuffer sync (restored behavior prior to r96693); create 3D window on CrFbWindow class instance creation.

Host 3D: Chromium server: Presentation framework: drop unused code.

Host 3D: Chromium server: Presentation framework: move classes into separate files for better code reading (to be continued).