TimelineView is not a general control that can be used with any model,
thus i do not need the complexity of Qt’s QQmlDelegateModel incubation
task to initialize required properties. I _would_ have used it if it
were available in C++, but since it is not, what i mean is that i do not
need to _reimplement_ all of it for my case: i already know what
required properties there are.