Autosave to temporary file

[MisterE123]

I keep losing my work because I forget to save the file at first and then the computer shuts down.

Solution: if Autosave is enabled, then autosave to a temporary file if the file has not been saved yet.

This would work hand-in-hand with #993, so you could retrieve files from the temporary file storage from "recently opened files"

[flxzt]

There is already a feature request for this open #545 - I'll close as duplicate.