feat: Signup query params tracking (#2098)

* feat: Add tracking of signup query params

* fix: Headers already sent to client

* fix: OAuth error wipes previously written query params cookie

server/migrations/20210430024222-marketing-tracking.js

@@ -0,0 +1,14 @@
+'use strict';
+
+module.exports = {
+  up: async (queryInterface, Sequelize) => {
+     await queryInterface.addColumn("teams", "signupQueryParams", {
+      type: Sequelize.JSONB,
+      allowNull: true,
+    });
+  },
+
+  down: async (queryInterface, Sequelize) => {
+    await queryInterface.removeColumn("teams", "signupQueryParams");
+  }
+};