document starter models

- add new script `scripts/make_models_markdown_table.py` that parses
  INITIAL_MODELS.yaml and creates markdown table for the model installation
  documentation file

- update 050_INSTALLING_MODELS.md with above table, and add a warning
  about additional license terms that apply to some of the models.

scripts/make_models_markdown_table.py

@@ -0,0 +1,23 @@
+#!/usr/bin/env python
+
+'''
+This script is used at release time to generate a markdown table describing the
+starter models. This text is then manually copied into 050_INSTALL_MODELS.md.
+'''
+
+from omegaconf import OmegaConf
+from pathlib import Path
+
+
+def main():
+    initial_models_file = Path(__file__).parent / '../invokeai/configs/INITIAL_MODELS.yaml'
+    models = OmegaConf.load(initial_models_file)
+    print('|Model Name | HuggingFace Repo ID | Description | URL |')
+    print('|---------- | ---------- | ----------- | --- |')
+    for model in models:
+        repo_id = models[model].repo_id
+        url = f'https://huggingface.co/{repo_id}'
+        print(f'|{model}|{repo_id}|{models[model].description}|{url} |')
+
+if __name__ == '__main__':
+    main()