🐛(frontend) rework the calendar integration approach

Use a totally different strategy, which hopefully works in prod env.
Actually broadcast channel cannot be shared between two different
browsing context, even on a same domain, an iFrame and a pop up
cannot communicate.

Moreover, in an iFrame session cookie are unavailable.
Rely on a newly created backend endpoint to pass room data.

src/sdk/library/.env.development

@@ -0,0 +1 @@
+VITE_VISIO_SDK_URL=https://meet.127.0.0.1.nip.io/sdk