Async-Storage plugin productization (prototype in CRW)

The async-storage plugin is not properly downstream and is not available in the product:

• create a new workspace and enable the async-storage
• ERROR: workspace failed to start

Productization tasks listed in this document:
https://github.com/redhat-developer/devtools-productization/blob/master/codeready-workspaces/processes/new-image-productization.adoc

Once images exist, there will likely be steps required to:

• enable async images in the operator/metadata/bundle images (where it's currently disabled as part of the sync*.sh script that convert Che to CRW).
• document new images in install guide / admin guide / release notes

Downstream images should be called (despite erroneous specs from before where storage was omitted):

• async-storage-server-rhel8 and
• async-storage-sidecar-rhel8