UI: Rename 'obs' dir to 'UI'

This is to prevent confusion both when prefixing commits and when
reading the directory structure for the first time.

UI/vertical-scroll-area.cpp

@@ -0,0 +1,10 @@
+#include <QResizeEvent>
+#include "vertical-scroll-area.hpp"
+
+void VScrollArea::resizeEvent(QResizeEvent *event)
+{
+	if (!!widget())
+		widget()->setMaximumWidth(event->size().width());
+
+	QScrollArea::resizeEvent(event);
+}