When downloading frames for stacking, we should check temp storage before committing.

We should abort a task if not enough temp storage is available to download the required number of files.
Even though it can be difficult to know for certain how much space is required, we should still be able to make an estimate based on the type and number of files to be downloaded.

This abort should come with a detailed log message.

https://lcoglobal.redmineup.com/issues/2707