Add support for the Badging API

**Is your feature request related to a problem? Please describe.**

When a user receives a new message there are no badge around the application icon when the PWA is installed

**Describe the solution you'd like**

Using the [Badging API](https://developer.mozilla.org/en-US/docs/Web/API/Badging_API)

**Describe alternatives you've considered**

A fallback might be to update the application icon on the fly, but that requires a lot more work

**Additional context**

This API is still fairly novel and a progressive enhacement approach would be preferable to avoid cross browser issues