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.hpp

@@ -0,0 +1,19 @@
+#pragma once
+
+#include <QScrollArea>
+
+class QResizeEvent;
+
+class VScrollArea : public QScrollArea {
+	Q_OBJECT
+
+public:
+	inline VScrollArea(QWidget *parent = nullptr)
+		: QScrollArea(parent)
+	{
+		setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+	}
+
+protected:
+	virtual void resizeEvent(QResizeEvent *event) override;
+};