Reimplement breadcrumbs for new room list
This all-new component handles breadcrumbs a bit more smoothly for the app by always listening to changes even if the component isn't present. This allows the breadcrumbs to remain up to date for when the user re-enables breadcrumbs.
The new behaviour is that we turn breadcrumbs on once the user has a room, and we don't turn it back off for them.
This also introduces a new animation which is more stable and not laggy, though instead of sliding the breadcrumbs pop. This might be undesirable - to be reviewed.
