TUN-10389: Implement main run method

This introduces  the main precheck logic. This will follow concurrency model, timeout handling, and retry logic established in the SPEC. We will follow the decision flow in the [connectivity pre-checks SPEC](https://wiki.cfdata.org/spaces/TUN/pages/1374967685/Connectivity+Pre-checks+for+cloudflared). You can find an attached image of what the decision flow should look like.

![image.png](/uploads/fa71215adc2da509f6cbbb74532e3d95/image.png){width=900 height=235}