Deployment to "All Targets" never starts

I issued a deployment to "All devices". I didn't notice but my board was still in pending but I was able to create the deployment anyway. The deployment acted as if it were against a dynamic group, showing as "Pending (awaiting devices)."

I then accepted the device into the fleet, where it shows in the "All devices" list but it is never added to the active deployment.

I aborted and re-created the deployment now that the device is in the fleet and it proceeds normally.

Acceptance criteria (backend):

• it is not possible to create deployment using /deployments/group/ {name} endpoint (https://github.com/mendersoftware/deployments/blob/48c04559a4038e6a66b5519f7465a5da50ea55f3/docs/management_api.yml#L165) and providing a list of devices or filter id - in that case, return Bad Request;
• return Bad Request if there are no devices belonging to a group when using /deployments/group/{name} endpoint;