[disconnected-csv] - RFE - provide this action via prebuilt image

[raffaelespazzoli]

currently when this action is used a step is added to the pipeline to build the container for this action:

Build container for action use: '/home/runner/work/_actions/redhat-cop/github-actions/master/disconnected-csv/Dockerfile'.

please provide a way to use a prebuilt container, this will save time in every build.

[sabre1041]

Support provided [Referencing a prebuilt container](by https://docs.github.com/en/actions/learn-github-actions/finding-and-customizing-actions#referencing-a-container-on-docker-hub)

Next step is to discuss naming convention for action images and to develop publishing process

[sabre1041]

also see #50 for some similar efforts