Enable qkd-pipeline to start shell scripts and not only ELF files
Current modules specified by qkd-pipeline have to be ELF binary executable files. This is due to the fact, that qkd-pipeline forks and calls execv sys-call. However, some modules may be scripts files (bash, python, ...). Currently these are not supported.
Implement a way to spawn script files as modules inside the qkd-pipeline tool.