Remove appbase as an external dependency.

lib/appbase/util/DistanceBetweenPoints.hpp

@@ -0,0 +1,20 @@
+#pragma once
+
+#include <QPointF>
+
+#include <cmath>
+
+namespace chatterino {
+
+inline float distanceBetweenPoints(const QPointF &p1, const QPointF &p2)
+{
+    QPointF tmp = p1 - p2;
+
+    float distance = 0.f;
+    distance += tmp.x() * tmp.x();
+    distance += tmp.y() * tmp.y();
+
+    return sqrt(distance);
+}
+
+}  // namespace chatterino