Preliminary Vast AI support

[kristopolous]

This is preliminary support for Vast. It currently works on an unreleased version of the SDK which we will soon get up to PyPy

The document https://docs.google.com/document/d/1oWox3qb3Kz3wXXSGg9ZJWwijoa99a3PIQUHBR8UgEGs/edit?pli=1&tab=t.0 was followed and all the testing passed

Tested (run the relevant ones):

• [x] Code formatting: bash format.sh
• [x] Any manual or new tests for this PR (please specify below)
• [x] All smoke tests: pytest tests/test_smoke.py
• [x] Relevant individual smoke tests: pytest tests/test_smoke.py::test_fill_in_the_name
• [x] Backward compatibility tests: conda deactivate; bash -i tests/backward_compatibility_tests.sh

I'm pretty sure there will need to be edits, I'm fine with that. This is attempt 1. The outstanding work:

We need to

• tidy up our dockerhub and will get a better image to launch.
• release the updates to the sdk and come up with a pip name for it.
• get our catalog to update in the git hook flow as described (my goal is every 6 hours)

[kristopolous]

Thanks for contributing to this @kristopolous ! This is really exciting. Left some discussions. One main confusion I have is that, does vast ai like runpod, a cloud providing pods to users as their "VM"s? Asking because I'm seeing a lot of docker related code, and just want to confirm :)

historically, runpod was a clone of vast. We currently offer docker-style containers and will be providing vms soonish (probably before end of year)

[kristopolous]

these test passing is blocked by https://github.com/skypilot-org/skypilot-catalog/pull/100/commits