Testlab backend requirements

BackendRequirement
dockerimages must contain sleep and sh (distroless unsupported — use vmlab)
vmlabtemplates must ship the QEMU guest agent; each group gets a throwaway one-VM lab
vmlab (Windows scenarios)guests must be Server 2019 / Windows 10 or newer

- docker backend

- vmlab backend

- Scenarios

§ 2Referenced by

- docker backend

- vmlab backend