Improve commandline option handling

[schaefi]

Description

For the firecracker pilot we need to transfer the commandline into the VM. This is done by passing the commandline via the kernel cmdline and parsing it as a Unix command. On the way through the calling shell, the kernel cmdline and the parsing in rust there are several pitfalls for lost quotation.

Let's find a way to make this more robust

Acceptance Criteria

• Try mybash -c "ls -l" as an example and get the correct ls output