[WIP] Stix miniapp in 2D

[mlstowell]

A miniapp designed to simulate electromagnetic wave propagation in magnetized plasmas using a frequency domain formulation on 2D domains.

[github-actions[bot]]

:warning: This PR has been automatically marked as stale because it has not had any activity in the last 300 days. If no activity occurs in the next 30 days, it will be automatically closed. Thank you for your contributions.