Timelapse render option

[WisdomCode]

This Request wants to take care of the suprisingly old #1313 It offers a combo box for setting what is to be done with the timelapse after a print is finished. To not break previous setups, the default is to render always after a print. However, it is now also possible to render only successful prints after the print is finished, or to never render a print after finishing printing.

However, I am still not done with this request, because there is a bug I cannot really get my head around. Maybe someone a bit more acquainted can help me out here?

Currently, the render is successfully skipped, however the according print files are still kept as currently active, as if the recording did not stop. This must be due to the timelapse being saved as "current" (the variable in src/octoprint/timelapse.py), but I cannot find where this is happening and how to stop it. A restart of the server fixes it, as the "current" variable gets reinitialized then. I am also not really sure how to test it without printing, which is just a bit painful for debugging this efficiently. I would appreciate any help. Thank you for this great project @foosel !