CircleAvatarwhich checks whether the user has a profile picture or not Actually if the user has a picture, it's not a
CircleAvatar, but a
MaterialType.circle, so that the image can be cached with a
CachedNetworkImage. There is also the user's initial as placeholder while downloading and in case of error.
Widgetthat returns a
Centerwidget with the initial of the name passed as parameter, to be used with PinderyCircleAvatar.