Add building guide for the ggml plugin

[hydai]

Explanation

Add docs for building ggml plugins.

Related issue

Fixes #203

What type of PR is this

/kind documentation

[alabulei1]

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 81e6879cd869ea406867c9a2cb3aecf745cd7040

Key changes in the patch:

• The patch adds a building guide for the ggml plugin in the wasi_nn.md file.
• The building guide includes instructions for building WasmEdge with the ggml plugin on different platforms (macOS, Linux).
• The guide provides different compilation options and commands for each platform, including Intel Model, Apple Silicon Model, Ubuntu/Debian with CUDA 12, Ubuntu on NVIDIA Jetson AGX Orin, Ubuntu/Debian with OpenBLAS, and General Linux without any acceleration framework.

Potential problems:

• The guide includes different compilation options and commands for each platform, which could lead to confusion and potential errors if not followed correctly.
• The guide assumes that the necessary dependencies (e.g., OpenVINO™, PyTorch, llama.cpp, OpenBLAS) are already installed, but it doesn't provide instructions for installing them.
• The guide doesn't mention any potential issues or troubleshooting steps.
• The guide doesn't provide any information about testing or verifying the plugin after building.

Overall, the patch adds a useful building guide for the ggml plugin, but it could benefit from providing more detailed instructions, including dependency installation and troubleshooting information.