Plugins » Docker

Fixes #18518 - Add proper validation for container image

For now the image has only been validate via the result
of the search, but not enforced on the server side.

The model validation brings now proper feedback when
the form has been submitted to the server.

Fixes #18733 - Prevent fallback to Docker Hub on registry search

When searching for an external registry the search would show
results from Docker Hub due to it searching via the compute
resource.

By using a registry parameter to indicate which search tab is...

Fixes #7912 - Wizard path error and tests