Need better handler for tmp files to unblock running under different users

[FFAMax]

https://github.com/exo-explore/exo/blob/bc1d88d86d6a016669974d7d3dbf87fc07b18bc7/exo/helpers.py#L38

If user A used exo, user B will unable to use exo due tmp file blocked by user A until manually removed or system reloaded (in cases tmp folder wiped during reload)