bulma (call): add a button for screen sharing: - add a button for screen sharing, only on desktop - split `muted` state to `inactive` and `muted` where `muted` is only about the color - use the `inactive` state with an other color (in `screen-off` class) to indicate when screen is not shared rel 432

{% import 'components/avatar.html' as avatar with context %}

{{ avatar.avatar(entity, "is-64x64") }}