chore: refactor workflow writting (#2225)

# What does this PR do?

Use a composite action to avoid similar steps repetitions and
centralization of the defaults.

Signed-off-by: Sébastien Han <seb@redhat.com>

.github/actions/setup-runner/action.yml

@@ -0,0 +1,22 @@
+name: Setup runner
+description: Prepare a runner for the tests (install uv, python, project dependencies, etc.)
+runs:
+  using: "composite"
+  steps:
+    - name: Install uv
+      uses: astral-sh/setup-uv@6b9c6063abd6010835644d4c2e1bef4cf5cd0fca # v6.0.1
+      with:
+        python-version: "3.10"
+        activate-environment: true
+        version: 0.7.6
+
+    - name: Install dependencies
+      shell: bash
+      run: |
+        uv sync --all-extras
+        uv pip install ollama faiss-cpu
+        # always test against the latest version of the client
+        # TODO: this is not necessarily a good idea. we need to test against both published and latest
+        # to find out backwards compatibility issues.
+        uv pip install git+https://github.com/meta-llama/llama-stack-client-python.git@main
+        uv pip install -e .