Experiment with colors in the marker chart

We want to add some colors to the marker chart.

There are different ways we could use colors:

* use a computed color from the name (and description) -- this can be especially useful for the first part of #4134
* use the category colors -- this can be especially useful for the second part of #4134
* use colors for each thread when several threads are selected

┆Issue is synchronized with this [Jira Task](https://mozilla-hub.atlassian.net/browse/FP-560)