New fullscreen chat WIP:

* Fullscreen chat: now uses a custom page (in other words: when opening the chat in a new tab, you will have the Peertube menu). WIP
* some code refactoring (getBaseRoute moved to util/uri, ...)

client/utils/uri.ts

@@ -0,0 +1,18 @@
+import type { RegisterClientOptions } from '@peertube/peertube-types/client'
+
+function getBaseRoute ({ peertubeHelpers }: RegisterClientOptions, permanent: boolean = false): string {
+  if (permanent) {
+    return '/plugins/livechat/router'
+  }
+  // NB: this will come with Peertube > 3.2.1 (3.3.0?)
+  if (peertubeHelpers.getBaseRouterRoute) {
+    return peertubeHelpers.getBaseRouterRoute()
+  }
+  // We are guessing the route with the correct plugin version with this trick:
+  const staticBase = peertubeHelpers.getBaseStaticRoute()
+  return staticBase.replace(/\/static.*$/, '/router')
+}
+
+export {
+  getBaseRoute
+}