Add a scheduler server skeleton

[angelhof]

Depends on #10. We will retarget once that PR is merged.

This PR adds a skeleton for a scheduler server (at the moment it does nothing).

TODOs before merging this PR

• Save the partial_order to a file in the temp directory that is called partial_order (not a random one)
• Create the partial order unparsing code here
• Set the skeleton of the schedule_work component
• Make sure that we merge future_spec to future in PaSh (Support for spec pash#660)
• Retarget deps/pash to future

After we merge this PR, we can focus on properly moving the scheduler loop functionality from orch to scheduler_server.py