Add caching to GraphQL API

[bdmason]

[chenzongxiong]

It's useful to cache data from ipfs.

In mcp case, a project will upload their whole data content to ipfs. As for the mcp service, it may only need one or two rows from the whole content. (take json file as example).

But the project will request metadata for different users regularly, and future requesting user is still inside the reuested ipfs content.

In this situation, we don't have to fetch content from ipfs again in a short time.

You can check this resource.

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