Setup self-hosted runners

[BigLep]

We want to validate that foc-localnet continues to work via CI. We have been finding that github action runners aren't powerful enough. We want to get self-hosted runners going like we have with lotus in filecoin-project. This is a tracking issue for that work.

[BigLep]

@galargh : can you please help with this or point us on how to best do it while following the same setup we have with filecoin-project? (I assume there are some one-time costs for this because this project is in a different GitHub organization.)