Add pure containerd + crun + llama server example

[CaptainVincent]

Add a pure crun demo case and verify the response, too.

[juntao]

Hello, I am a code review bot on flows.network. Here are my reviews of code commits in this PR.

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Commit 6309347d4d2ffd8ce0f615f45614cef3a998525e

Key Changes:

1. Added a new GitHub workflow file named "crun-containerd-llama-server.yml" that runs a test for a pure containerd + crun + llama server example.
2. The workflow includes steps to install required packages, containerd, WasmEdge, crun with plug-in support, and nn-preload support.
3. Downloads the llm model and a wasm application for testing.
4. Runs the llama API service with crun and then tests the API server by sending requests and checking the results.
5. Displays the versions of crun, wasmedge, and ctr.

Potential Problems:

1. The script directly installs packages with sudo privileges, which can be risky as it grants elevated permissions without user interaction.
2. The workflow may require environment-specific configurations or dependencies that are not documented.
3. There is a command to run a container with specific configurations, such as network host and environment variables, that may not be suitable for all environments.
4. The script downloads files from external sources without verifying their integrity, which can pose security risks.
5. The workflow lacks error handling or validation of intermediate steps, which can lead to failures that are not handled gracefully.