Add Ability to Pass Environmental Variables Into the Worker From the Factory

[klannon]

See https://github.com/matz-e/lobster/issues/600, in particular @matz-e's last comment.

It would be nice to have some way to pass a list of environmental variables into the worker environment from the factory. Here is one example use case: Suppose the task uses an environmental variable to determine the squid proxy location. If you could tell each factory to set the environmental variable to the appropriate value, it would allow configure different factories for different resource environments (e.g. different squid servers).

@khurtado might also want to comment on whether I have the right idea here.

I know there's a lot of pressure with other deadlines, so no rush here. No work is stuck. I just wanted to file it before I forgot about it.

[dthain]

Should be pretty straightfoward, since the batch job interface has an explicit place to pass environment variables along to the underlying job.

[dthain]

@nkremerh Please implement this one. Suggest that you allow the factory to have multiple arguments of the form --env X=Y that just add elements to JX dictionary, and then pass that through to batch_job_submit. (@btovar has plenty to do right now.)