chore: move all Llama Stack types from llama-models to llama-stack (#1098)

llama-models should have extremely minimal cruft. Its sole purpose
should be didactic -- show the simplest implementation of the llama
models and document the prompt formats, etc.

This PR is the complement to
https://github.com/meta-llama/llama-models/pull/279

## Test Plan

Ensure all `llama` CLI `model` sub-commands work:

```bash
llama model list
llama model download --model-id ...
llama model prompt-format -m ...
```

Ran tests:
```bash
cd tests/client-sdk
LLAMA_STACK_CONFIG=fireworks pytest -s -v inference/
LLAMA_STACK_CONFIG=fireworks pytest -s -v vector_io/
LLAMA_STACK_CONFIG=fireworks pytest -s -v agents/
```

Create a fresh venv `uv venv && source .venv/bin/activate` and run
`llama stack build --template fireworks --image-type venv` followed by
`llama stack run together --image-type venv` <-- the server runs

Also checked that the OpenAPI generator can run and there is no change
in the generated files as a result.

```bash
cd docs/openapi_generator
sh run_openapi_generator.sh
```

llama_stack/strong_typing/mapping.py

@@ -0,0 +1,40 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
+"""
+Type-safe data interchange for Python data classes.
+
+:see: https://github.com/hunyadi/strong_typing
+"""
+
+import keyword
+from typing import Optional
+
+from .auxiliary import Alias
+from .inspection import get_annotation
+
+
+def python_field_to_json_property(python_id: str, python_type: Optional[object] = None) -> str:
+    """
+    Map a Python field identifier to a JSON property name.
+
+    Authors may use an underscore appended at the end of a Python identifier as per PEP 8 if it clashes with a Python
+    keyword: e.g. `in` would become `in_` and `from` would become `from_`. Remove these suffixes when exporting to JSON.
+
+    Authors may supply an explicit alias with the type annotation `Alias`, e.g. `Annotated[MyType, Alias("alias")]`.
+    """
+
+    if python_type is not None:
+        alias = get_annotation(python_type, Alias)
+        if alias:
+            return alias.name
+
+    if python_id.endswith("_"):
+        id = python_id[:-1]
+        if keyword.iskeyword(id):
+            return id
+
+    return python_id