Improve codeready-workspaces-images local build story for better ease of use (and to allow GHA builds)

If some CI wants to build the images, these CI may not have access to Red Hat internal repositories, or a developer may want to check if the image is building.

But today, there is a need to uncomment something in Dockerfile and we may not have access to the repositories added.

https://github.com/redhat-developer/codeready-workspaces-images/blob/crw-2-rhel-8/codeready-workspaces-plugin-java11/Dockerfile#L36-L37

And sometimes it's not clear what to do:

https://github.com/redhat-developer/codeready-workspaces-images/blob/928b5bfdbc2023c96fde662063635793bd07d454/codeready-workspaces-devfileregistry/build/dockerfiles/Dockerfile#L46-L48

and these repositories may not be accessible outside or Red Hat VPN

https://github.com/redhat-developer/codeready-workspaces-images/blob/crw-2-rhel-8/codeready-workspaces-plugin-java11/content_sets.repo

Sometimes the specified rpm is not available like in codeready-workspaces-stacks-golang

8 4.383 No match for argument: openshift-clients-4.9.0-202109101042.p0.git.96e95ce.assembly.stream.el8
8 4.390 Error: Unable to find a match: openshift-clients-4.9.0-202109101042.p0.git.96e95ce.assembly.stream.el8

These Dockerfiles also have

FROM ubi8-minimal:8.4-210

while building outside of brew we need to prefix it by registry.redhat.io
FROM registry.redhat.io/ubi8-minimal:8.4-210

So it would be great to have a generated, alternative Dockerfile for these cases like local.Dockerfile, with nothing to uncomment, nothing to replace,etc.

it should work out of the box to build the image.

REQUIREMENTS

• local.Dockerfile file must be generated at the same time as the brew-friendly Dockerfile in the root of crw-images/*/ folders (during sync.sh)
  • script to convert Brew to local dockerfile (localize.sh?) should be in root of crw-images repo for reuse, rather than having the same code 31 times in 21 folders
  • include a generic build.sh script that can be passed in the path to work folder (eg., ./build.sh -s codeready-workspaces-images/codeready-workspaces-plugin-java11)
  • build.sh must check for podman and use that if found; fall back to docker if podman not installed
  • build.sh must provide usage details w/ sample invocation
  • https://github.com/redhat-developer/codeready-workspaces-images/blob/crw-2-rhel-8/README.building.md should be created and linked from README.md to explain how to use the localize.sh script, and then how to run a local build w/ the build.sh script

RULES for localize.sh

• use fully-qualified base image, including registry (ideally using non-auth'd one for easier build experience)
  • special transformation rules may be required for rhel8 or ubi8 namespaced images

• apply all required content sets to allow rpm resolution
  • all content_set*.repo files should be consistent
  • content_set*.repo files where content is DISABLED should be removed and not copied during the Brew container builds (why bother if the repo is disabled?)
    • https://github.com/redhat-developer/codeready-workspaces-images/blob/crw-2-rhel-8/codeready-workspaces-devfileregistry/build/dockerfiles/content_sets_rhel8.repo
    • https://github.com/redhat-developer/codeready-workspaces-images/blob/crw-2-rhel-8/codeready-workspaces-pluginregistry/build/dockerfiles/content_sets_rhel8.repo

• for containers that install oc or helm, a workaround may be needed for when the version of rpm is not present on the public registry (vs. the internal RH pulp registry): remove hardcoded versions? search for an older/different version with https://github.com/redhat-developer/codeready-workspaces/blob/crw-2-rhel-8/product/getLatestRPM.sh ?