Create a JSON library for tools

As the number of tools is increasing in order to manage to show the tool in a more dynamic way, I would suggest creating a JSON file and store the tool's information inside the JSON objects.

One key advantage of such implementation is that in the future we can show all tools on the first page by looping through the JSON array of tools. Then the contributors just need to update the JSON file and their tool will be shown on the first page automatically.

Suggested Format:

```json
{
"conversionTools": [
{
"title": "Angle Conversion",
"description": "bla bla",
"url": "/Angle_Conversion/angleconversions.html"
}
],
}
```

未指定任何文件或测试。首先查找当前工具的列出方式以及第一页如何渲染这些工具，然后定义 JSON 数据结构并将现有显示连接到该结构；完成标准是工具可以在 JSON 中表示并动态显示。

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