Element Call SPA integration

[jmartinesp]

For technical reasons on Android, we need an app to host the Element Call SPA so that calls can continue when the app is in background or the device is locked (there is still no guarantee that the system does not decide to kill the app).

For product reasons, we want users to open EC links within the EX app.

We need to be able to:

• Open an EC SPA link into a webview in EX.
• Keep the call running on background or when the device is locked, but without camera input.
• Handle call.element.io universal links.
• Handle custom scheme element://call?url=some-encoded-url for customers hosting their own EC instance.