Implement Asyncio Instead of Threads

[kb1lqc]

There's no reason this needs to be threaded to properly check and send TUN packets. asyncio, pytest-asyncio, and pyserial-asyncio should be able to handle this very well. I previously tried to implement asyncio into the TUN adapter but it did not work out well. I was mainly hindered by the inability to test it since I want to maintain as much Test Driven Development as possible.

Timeline

This is not absolutely imperative but it would be a good idea to include it in before we get too far along. For now threads will likely work. This issue ticket is a good reminder that we should move towards newer technology when possible.