Retroactive spool management and "spool timeline"

[Mearman]

Is your feature request related to a problem? Please describe.
I forget to update the active spool or don't have time in the middle of a print

Describe the solution you'd like
Add a timeline of spool usage and allow adding of markers for spool changes e.g. add a marker at 2020/05/17 17:00 that "spool B" was made active from that point onward.
For visual clarity, the colour of the line on the timeline could be changed.