[FEATURE] Use different base docker image

[jacksonjacobs1]

Description

The base docker image https://hub.docker.com/r/rayproject/ray-ml has been deprecated. It will still receive pushes but will not receive support from ray.

This is not an immediate issue for us because we've pinned the base image version in QA.

However, another motivation for changing the base image is to reduce image bloat. ray-ml includes both pytorch and tensorflow, resulting in a very large image.

Implementation

Use a ray image rather than ray-ml. Add the pytorch installation to the dockerfile.