Installing stress-test tasks: Need to be in a folder that's accessible to the server

[jluethi]

Cool to see the task registration using on-disk tasks. One limit I found when setting up the stress test at FMI: The server needs to have access to those files, otherwise we get a:

[Errno 13] Permission denied: '/Path/to/fractal-stress-tests/fractal-demos/examples/99_stress_test/fractal-tasks-stresstest/dist/fractal_tasks_stresstest-1.0.0-py3-none-any.whl'

I'll keep track of workarounds here, depending on how we do things, we can think about updating the example or leaving a README note.

[jluethi]

One workaround:
Use this

FRACTAL_ACCESSIBLE_BASE_FOLDER=`pwd`
fractal task collect $FRACTAL_ACCESSIBLE_BASE_FOLDER/fractal-tasks-stresstest/dist/fractal_tasks_stresstest-${VERSION}-py3-none-any.whl

And instruct the user to set the FRACTAL_ACCESSIBLE_BASE_FOLDER to a fractal-demos/examples/99_stress_test folder that is accessible to the server. That allows for correct task installation.