Add summary of image names and tag patterns

[matthewfeickert]

If a user has credentials to https://hub.opensciencegrid.org they can login and view all images under the ustalas project (https://hub.opensciencegrid.org/harbor/projects/612/repositories). However, if summaries of image names and tag patterns could be made available in the README that would be generally helpful. e.g. there are images of the naming scheme

hub.opensciencegrid.org/usatlas/af_{base}_tf_{facility}:latest

for base in {jupyter, cuda, centos7} and facility in {bnl, uc, slac}.

While this information does exist in the CI configs

ML-Containers/.github/workflows/main.yml

Line 14 in b4ca7cc

base: ["centos7", "centos9", "cuda", "jupyter"]

ML-Containers/.github/workflows/main.yml

Line 74 in b4ca7cc

facility: ["uc", "bnl", "slac"]

it would be useful to document this as well.