Add tmpfs when running a container

Despite the tests run in the various aspects of the BEAT code base which showed that having the container start read-only was successful, actual run on the platform started to unsuccessfully fail with an error related to temporary file creation coming from the entrypoint script loading the correct conda environment.

"Unsuccessfully failed" here means that the full experiment run was marked as good despite that error happening which in fact did not even allow for a proper start of the execution procedure.

The fix for this situation is to add a minimal writable tmpfs for /tmp in order to have the space necessary for that file to be created.

It might also be useful to have one for /run even if it does not look like it is being used currently (at least in the same way as /tmp seemed to not be used).