Switch runner exec mode from docker to shell
This is to allow more flexibility, specifically, you can run docker from the runner
During the maintenance period on Monday, 14 Oct 2024, all new projects will no longer create a container registry as part of the project area. Already existing projects will be unaffected at this time. Instead, users should utilize the official ORNL container registries at camden.ornl.gov (internal/moderate) and savannah.ornl.gov (external/low). Please see ORNL Today article for more info.
This is to allow more flexibility, specifically, you can run docker from the runner