meson: Make libdisplay_info a feature option

From the commit message:

Some features depend on libdisplay-info, and making it a feature
option should increase its visibility and adoption.

This makes it required when building with "-Dauto_features=enabled",
unless explicitly disabled with "-Dlibdisplay_info=disabled".

If "-Dauto_features=enabled" is not set, everything remains the
same.

In the future, the libdisplay_info option can be made "enabled" by
default so that it would always be required unless explicitly
disabled.

This is useful for: !3576 (merged)

MR for g-b-m: gnome-build-meta!2671 (merged)