Use tempfs for cache files

[davidgantman]

Is your feature request related to a problem? Please describe.
PatchWise currently creates a sandbox directory relative to the package installation path i.e. PatchWise/.venv/lib/python3.10/site-packages/patchwise/sandbox. The sandbox directly is largely used for temporary files like the sandbox kernel git worktree and build output.

Describe the solution you'd like
Move the sandbox directory to tempfs so that disk space is not unnecessarily consumed by PatchWise. Only files that are not expected to be persistent between reboots should be included in the migration as tempfs does not survive between system restarts.

[unnathi84]

I can work on this.