Add Google FLoC opt-out header on web page requests. Closes #939

router/middleware/disableFloc.go

@@ -0,0 +1,8 @@
+package middleware
+
+import "net/http"
+
+// DisableFloc will tell Google to not use this response in their FLoC tracking.
+func DisableFloc(w http.ResponseWriter) {
+	w.Header().Set("Permissions-Policy", "interest-cohort=()")
+}