feat: moment marker should move dynamically over time

[L-ZJoker]

No description provided.

[zunnzunn]

useNow() is suitable for this use-case, however, you might want to configure this behavior to be more specific. A few things to consider:

1. Try playing around with this. If you set a narrow time window (chart-start and chart-end) in the gantt chart, e.g. a few minutes around the current time), you will notice that the time marker does not move in a, say, 1-second-interval as you'd expect it to.
2. What if the current time is not within the set time window and therefore not visible anyways? The periodic recomputation of the xDist of the time marker is a waste of resources then. It'd make sense to check whether the current time is within set boundaries.