Migrates CI runners to use AWS

Some notes:

• Use [self-hosted, intel-cpu, 8-cpu, ci] to utilize a CPU runner. These aren't stored in our local runners and are spun up by demand, hence why they do not show up in settings
• Use [self-hosted, single-gpu, nvidia-gpu, t4, ci] for GPU runners. (Don't try and specify/fine-tune nightly vs main CI runners, just leave it as CI)
• In general now these CI runners assume no persistent storage to make things easier