display: Use ComboBox when folded

On small window sizes the ButtonBox can overflow the panel. This is especially true in single display mode when no other elemnts prevent shrinking to e.g. 360px width on phones. Use the ComboBox introduced in 632cb3c9 in these cases.

For that we introduce cc_display_settings_refresh_layout() to refresh the layout when the folded state changes. This can later on be used for more tweaks to shrink to smaller sizes.

recording

(for the video i temporarily allowed more buttons in the button bar since my monitor would advertise too many scalings and combo box would always be used in that case)

/cc @bertob @bberg

Closes: #1443 (closed)