Reorganized structure, seperating implementations from core logic

pkg/data/events/mbosnapshot.go

@@ -0,0 +1,14 @@
+package events
+
+type MBOSnapshot struct {
+	Orders []OrderEntry
+	Seq    uint64
+}
+
+type OrderEntry struct {
+	OrderID string
+	Side    Side
+	Price   float64
+	Size    float64
+	IsMaker bool
+}