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>

webpack.config.js

@@ -52,6 +52,9 @@ module.exports = {
     serviceworker: [
       resolve(__dirname, 'web_src/js/serviceworker.js'),
     ],
+    'eventsource.sharedworker': [
+      resolve(__dirname, 'web_src/js/features/eventsource.sharedworker.js'),
+    ],
     icons: [
       ...glob('node_modules/@primer/octicons/build/svg/**/*.svg'),
       ...glob('assets/svg/*.svg'),