Consider spec-level when checking whether a device is valid

[elezar]

At present, a CDI device specification is considered invalid when it contains no container edits, however, since the union of top-level spec conainerEdits and device-level containerEdits are applied to a container, we could relax this restriction to consider a device valid as long as the union of edits is non-empty.

[cyclinder]

Hi @elezar I want to working on this, can I pick this?

[elezar]

Hi @cyclinder we're still discussing whether this is something that we want to include in the spec. You're welcome to have a look at it already, but keep in mind that we might decide to not go this way.