Add version command with comprehensive unit tests and build integration

- Implement llama version command with table and JSON output formats
- Add build-time git information capture via scripts/generate_build_info.py
- Include comprehensive unit test suite (test_version.py, test_version_simple.py, test_version_integration.py)
- Add build system integration with custom setup.py command
- Update .gitignore to exclude generated build info file

Features:
- Display Llama Stack and client versions
- Show Python version and build information (git commit, date, branch, tag)
- Optional component/provider listing organized by API
- Support for both table and JSON output formats
- Build-time capture of git metadata for version tracking

Testing:
- 8 unit tests covering all functionality
- Integration tests for CLI execution
- Simple dependency-free validation tests
- Documentation for test suite and build process

Signed-off-by: Akram Ben Aissi <akram.benaissi@gmail.com>

setup.py

@@ -0,0 +1,53 @@
+#!/usr/bin/env python3
+
+# 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.
+
+import subprocess
+import sys
+from pathlib import Path
+
+from setuptools import setup
+from setuptools.command.build_py import build_py
+
+
+class BuildWithBuildInfo(build_py):
+    """Custom build command that generates build info before building"""
+
+    def run(self):
+        # Generate build info before building
+        self.generate_build_info()
+        # Run the standard build
+        super().run()
+
+    def generate_build_info(self):
+        """Generate build_info.py with current git information"""
+        script_path = Path(__file__).parent / "scripts" / "generate_build_info.py"
+
+        try:
+            # Run the build info generation script
+            result = subprocess.run(
+                [sys.executable, str(script_path)],
+                check=True,
+                capture_output=True,
+                text=True,
+            )
+            print("Build info generation completed successfully")
+            if result.stdout:
+                print(result.stdout)
+        except subprocess.CalledProcessError as e:
+            print(f"Warning: Failed to generate build info: {e}")
+            if e.stderr:
+                print(f"Error output: {e.stderr}")
+            # Don't fail the build, just continue with default values
+
+
+if __name__ == "__main__":
+    setup(
+        cmdclass={
+            "build_py": BuildWithBuildInfo,
+        },
+    )