add additional run parameters for manifest.json

[alex-fddz]

This change allows to specify additional docker run parameters in the image directories' manifest.json as follows:

"additionalRunParams": [
    {"--param1", "pValue1"},
    {"--param2", ""}
]

This enables more flexibility, for instance, one can add the parameter --hostname and set its value.

I am making this PR because my Lab uses a program that requires the docker container to be run with the --privileged parameter. I would like to have this running in the platform.

BTW, I also fixed the variable name in the for loop for Manifest.environment_vars (previously set as mountData).

[echuber2]

my Lab uses a program that requires the docker container to be run with the --privileged parameter. I would like to have this running in the platform.

I don't work for Coursera, but I think Coursera provided these scripts for local testing only, so any changes you propose won't be reflected on their platform. I would guess that they will not allow privileged containers to run on their host, but who knows? If you have a support representative at Coursera, they should be able to help you or discuss what you're trying to implement.

[alex-fddz]

I see.
We do have contact with a support rep at Coursera, I'll check with them and come back to this.
Thank you.