Referenced entities should be looked up also through the Auto-Complete facet

[oscarbou]

Current implementation exports and imports properties referencing other entities by writing:

1. on the Excel cell's value the title of the entity.
2. on the Excel cell's comment, the internal Id. of the referenced object.

As those internal ids are can be automatically generated by the datastore, the wouldn't be known when defining an initial set of entities to be imported (for example, imagine a TodoItem that references a "parent " TodoItem; all them are going to be initially imported from Excel).

The proposed solution complements current logic by trying to find the corresponding entity by means of the AutoComplete facet (if defined for the Entity). That's the more generic way on Apache Isis to search for a concrete entity using a simple String.

[danhaywood]

moved to incodehq/incode-platform#48