Move EventSource to SharedWorker (#12095)

Move EventSource to use a SharedWorker. This prevents issues with HTTP/1.1
open browser connections from preventing gitea from opening multiple tabs.

Also allow setting EVENT_SOURCE_UPDATE_TIME to disable EventSource updating

Fix #11978

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

web_src/js/index.js

@@ -2432,7 +2432,6 @@ $(document).ready(async () => {
   initContextPopups();
   initTableSort();
   initNotificationsTable();
-  initNotificationCount();
 
   // Repo clone url.
   if ($('#repo-clone-url').length > 0) {
@@ -2477,6 +2476,7 @@ $(document).ready(async () => {
     initClipboard(),
     initUserHeatmap(),
     initServiceWorker(),
+    initNotificationCount(),
   ]);
 });