use temporary (/tmp) directory of the host system instead of container

[sandepat]

1. Some applications might create temporary files inside the container folder (even on cvmfs as inside container user is root).
2. This could create storage and security issues, hence needs to be addressed
3. One of the possible solutions could be to bind mount (-v /tmp:/tmp), which will mount host system /tmp on container, letting us use host system tmp. This option can be added inside the wrapper script on the part of 'bosh exec launch'. Bosh passes these options to docker (udocker) run.