[DOC] Update with readme with pypi links

[jamesETsmith]

Description

Updating the readme with the following:

• Add the pypi wheel instructions
• Add links to the docker hub repo (for our images and the rocm/pytorch base images)
• Add explicit mention that this is a fork

Checklist

Please feel free to remove inapplicable items for your PR.

• The PR title starts with [$CATEGORY] (such as [NN], [Model], [Doc], [Feature]])
• The PR is complete and small, read the Google eng practice (CL equals to PR) to understand more about small PR. In DGL, we consider PRs with less than 200 lines of core code change are small (example, test and documentation could be exempted).
• Code is well-documented
• To the best of my knowledge, examples are either not affected by this change, or have been fixed to be compatible with this change