Implement Caching feature to the Proxy API

[trkaplan]

Multiple requests will still causes rate limit errors. I was planning to use https://vercel.com/integrations/upstash with this project -> https://github.com/trkaplan/opensea-api-proxy for the same purpose.

You can check the proxy API commit that @ssdsr made here: https://github.com/citydaoproject/app/pull/105/commits/e5bf582d4d518d8eae27a7fc43ed1d100e79e731 (this is a good way to hide the API key from the client. But we need more, caching. )

Related links that may help: vercel/next.js#12134 https://upstash.com/blog/netlify-graph-upstash