[DESK] Show monitor on "Settings" page when only one monitor detected

[DESK] Show monitor on "Settings" page when only one monitor detected

Hide multiple monitor selection controls in this case.
Otherwise, show them when multiple monitors are detected
and hide the monitor preview bitmap.

This fixes the focus on the resolution slider when tested in Windows XP.

Also use the monitor bitmap globally, because it's used on multiple pages.

CORE-17939 CORE-10606