Add a "base model" and "parent model" fields to machine-learning-model component

Proposal: ML models have lineages as well, like software libraries. They almost always have a base (aka foundation) model, and may have a parent model that's different from the original base model. Knowing this lineage is very important to understanding how a model works, how it was constructed, and inherited licenses/biases/risks/etc.

Ask: Add a "base-model" and "parent-model" field to mlm component
Required: True
Type: String, containing the unique identifier (e.g. author/name) of the model