automatically delete and replace old PLOT

[chiawang790204]

Add new function: automatically delete and replace old PLOT

[gregstarr]

I had the same idea, some of my plots die and don't make progress for several days. It would be cool if we could set a time limit after which non-finished plots are cancelled and cleaned up

[Chilli71]

This would be very helpful replacing individual plots with pool plots.
Since the manager can not influence the behavior of the chia plotting or madmax plotter the manager would have to delete the oldest plot in the final directory upfront if space is insufficient.