Support for enforcing thread affinity

**Is your feature request related to a problem? Please describe.**
Multi-threaded applications can interfere with each other if you run >1 per node.

**Describe the solution you'd like**
Port/allow access to Parsl's CPU affinity support.

**Describe alternatives you've considered**
Baking thread affinity into the functions being run.

No files, tests, or entry points are named. Start by locating Globus Compute's execution path and existing CPU-affinity integration, then compare it with Parsl's support; done means allowing thread affinity to be configured without requiring users to bake it into their functions.

Written by the indexing model from the issue text.