Add field for `Components.modelCard.baseModel`

**Proposal**
Base (aka foundation) models are one of the most important pieces of information to know about a given model, according to our research with dozens of AI/ML practitioners. Knowing whether a model is based on Llama2 or Stable-DIffusion or an unknown model that is worth investigating further before determining whether one can trust the current model.

**Details**
FieldName: Components.modelCard.baseModel
FieldType: List. Contains sub-fields Name, Version, and Source.
Required: Yes

**Example snippet**

```json
"modelCard" : [
"baseModel": [
"name": "Stable-diffusion-base",
"version": "x1",
"source": "https://huggingface.co/models/stable-diffusion-base-x1"
]
]
```