Document the docker images and how to find them

[sarasensible]

Is your feature request related to a problem? Please describe.
I had to google extensively to find out what the cmctl docker image was called.

Describe the solution you'd like
The docker image names and links should be easily available in the documentation

Describe alternatives you've considered
N/A

Additional context
It would also be nice if the latest tag could be linked as latest in the docker image.

For anyone else looking for the cmctl image, it's actually called cert-manager-ctl
quay.io/jetstack/cert-manager-ctl

[SgtCoDFish]

Agree it would be good to be clearer that this one has a different name to what people would expect.

It would also be nice if the latest tag could be linked as latest in the docker image.

This is an interesting one - it makes sense for this image specifically even though we intentionally avoid latest for all other images 🤔