Add PWA, service worker and Web Push

- Use new notification request/opt-in flow for push
- Implement unsubscribing
- Implement muting
- Implement emojis in title
- Add iOS specific PWA warning
- Don’t use websockets when web push is enabled
- Fix duplicate notifications
- Implement default web push setting
- Implement changing subscription type
- Implement web push subscription refresh
- Implement web push notification click

server/server_account.go

@@ -170,6 +170,13 @@ func (s *Server) handleAccountDelete(w http.ResponseWriter, r *http.Request, v *
 	if _, err := s.userManager.Authenticate(u.Name, req.Password); err != nil {
 		return errHTTPBadRequestIncorrectPasswordConfirmation
 	}
+	if s.webPushSubscriptionStore != nil {
+		err := s.webPushSubscriptionStore.ExpireWebPushForUser(u.Name)
+
+		if err != nil {
+			logvr(v, r).Err(err).Warn("Error removing web push subscriptions for %s", u.Name)
+		}
+	}
 	if u.Billing.StripeSubscriptionID != "" {
 		logvr(v, r).Tag(tagStripe).Info("Canceling billing subscription for user %s", u.Name)
 		if _, err := s.stripe.CancelSubscription(u.Billing.StripeSubscriptionID); err != nil {