Using a Github App to authorize users instead of self-hosting on Vercel

### Is your feature request related to a problem? Please describe.

Self-hosting an instance of the software to circumvent rate limits is restrictive.

### Describe the solution you'd like

I played around with the Github App API in a project as a POC [here](https://github.com/khosbilegt/github-to-mermaid). Creating a github-readme-stats Github App and allowing users to authenticate with their Github user could be a better flow than self-hosting an exact copy.

Don't know if there are any technical concerns relating to costs, but it could be doable.

### Describe alternatives you've considered

_No response_

### Additional context

_No response_