DEPL — No Traceability if optional labels are blank

The Execution Data Model explains that the Planner may construct
label attributes from the Component Data Model's label attributes.
This is problematic, and does not provide traceability if the
original label attributes are empty. An alternative is to name
each subelement. This is easy e.g. in the ComponentAssemblyDes-
cription, by changing the label attribute to name. For the
implementations in a package, or for artifacts in a monolithic
implementation, a qualified association could be used, were they
available in MOF (they are not); new classes would have to be
introduced, such as a NamedComponentImplementationDescription
class that is contained by the ComponentPackageDescription, has
a name attribute and a reference to the "real" ComponentImple-
mentationDescription.

Proposed resolution:

In the elements of a ComponentAssemblyDescription (Subcomponent-
instantiationDescription, AssemblyConnectionDescription, Assembly-
PropertyMapping), change the "label" attribute to a "name" attri-
bute, and clarify that the name must be unique among these ele-
ments.

Introduce a new class NamedComponentImplementationDescription
with a 1..1 association to ComponentImplementationDescription.
Edit ComponentPackageDescription by making its 1..* "implements"
relationship point to the new class.

Introduce a new class NamedImplementationArtifactDescription
with a 1..1 association to ImplementationArtifactDescription.
Edit MonolithicImplementationDescription by making its 1..*
"primaryArtifact" relationship point to the new class. Edit
ImplementationArtifactDescription by making its 0..* "dependsOn"
relationship point to the new class.

Throughout the ExecutionDataModel, clarify that these names are
used (instead of labels) to generate a human readable path that
identifies the source element.