Integration with Parsl

[hategan]

Use PSI/J as "provider(s)" in Parsl.

[hategan]

Comment from Ben: "i'd like to: get this released as a package that can be pip installed alongside parsl and psij, as a concrete goal/packaging task"

[benclifford]

my work in progress is in this repo at the moment: https://github.com/benclifford/parsl-psij-provider

At least two missing pieces:

psi/j providers a launcher mechanism along the lines of parsl's launcher mechanism. I need to reconcile how those will work together.

This code works for me in the successful path on slurm. I haven't done much in the way of error handling.