Identity data of a Definition object

[kirlat]

We need to include definition provider's IRI into the identity data of a Definition object.

Here is some background on that:
@balmas:

I think we should also include the resource provider uri in the identity data for the definition to start. There may be additional changes to the way we calculate the IRI for definitions down the road, but that would be a reasonable place to start.

It is meaningful where a definition comes from because the lexicons from which the definitions are derived have different reputations and purposes. For example, we have one dictionary for Greek which is specifically for Homeric text and others which are specifically for biblical texts and others which are for more early learners, and others which are for advanced scholars and what might be "corrected" with an annotation could be a typo in a digitization error, or it could be a user preferring a different meaning for their own purposes

Once provider's URI would be included into generation of the content-base IRIs, the provider should be attached to the Definition object during its creation and not changed after that. By all means Definition seems to be a value object, and that also means once fields that represent the value are set they should never be changed during the object's lifetime. Changing the values of identity fields should result in the creation of a new value (i.e. Definition) object. It might also mean that the provider object attached to a definition should stop being a proxy.