feat: add the VisualizationTypes type

Author: andreishket

vis/js/@types/visualization-types.ts

@@ -0,0 +1,7 @@
+/*
+  There are two visualization types in the project:
+    1. timeline - this is a Streamgraph map;
+    2. overview - this is a map with "bubbles".
+*/
+
+export type VisualizationTypes = "timeline" | "overview";