Move rendering from sc_display to sc_screen

Three components are involved in displaying device content on screen:
 - a window
 - a renderer
 - a texture

Originally, all three were handled by sc_screen.

Commit 051b74c88338702508d98bd532057b343e0a177c later extracted the
renderer and texture into a separate component, sc_display.

However, the split was a bit awkward because the window size and
rendering location were managed by separate components.

Move rendering back to sc_screen, keeping only texture management
separated.

PR #6651 <https://github.com/Genymobile/scrcpy/pull/6651>