Interval backups

[cppcooper]

trafficstars

Automating DF save backups on configurable intervals would be a very desirable feature.

Personally, I'd like to have the ability to:

1. rotate N saves with quicksave like @myk002 suggested
2. auto quicksave on an interval (if that isn't already a thing)
3. backup the current save on an interval

My usecase would be something like:

• Rotate 2 saves.
• Autosave every week.
• Backup every season.

[cppcooper]

I understand there are timelines now, so this could[/maybe should] trigger a timeline save on the intervals.

[ab9rf]

timeline saves are currently badly broken, but if and when bay12 fixes them this might be worth considering