feat: improve names of Docker sandbox containers

Updates the Docker sandbox backend to generate a name based on the experiment name, eval name, and eval index, instead of the randomly generated Docker container names. Makes it easier to skim through docker ps to try and see which evals are still running.

@vercel/sandbox has support for names and tags but only in beta, I'm happy to add that in if desired, but it'd mean upgrading to v2 of the package.