[Entanglement] Add entanglement bundle

The entanglement bundle defines move, copy, and link actions, and
exposes them as context menu actions.

* The Move action moves an object from it's current parent to a new
parent object.
* The Copy action deep-copies an object to a new parent object.
* The Link action links an object to a new parent object.

These actions are implemented by three new services: moveService,
copyService, and linkService.

Mocks are provided for each service for easy testing of components
that depend on them.

Additionally, this bundle provides a DomainObjectFactory that simplifies
the construction of mockDomainObjects for tests.

These actions are exposed to the user as context menu options.

platform/entanglement/README.md

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+# Entanglement
+
+Entanglement is the process of moving, copying, and linking domain objects
+in such a way that their relationships are impossible to discern.
+
+This bundle provides move, copy, and link functionality.  Acheiving a state of 
+entanglement is left up to the end user.
+
+
+## Services implement logic
+
+Each method (move, copy, link) is implemented as a service, and each service
+provides two functions: `validate` and `perform`.
+
+`validate(object, parentCandidate)` returns true if the `object` can be 
+move/copy/linked into the `parentCandidate`'s composition.
+
+`perform(object, parentObject)` move/copy/links the `object` into the 
+`parentObject`'s composition.
+
+## Actions implement user interactions
+
+Actions are used to expose move/copy/link to the user.  They prompt for input
+where necessary, and complete the actions.