Use GitHub API to get more details about each repo

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Once a contributor submits a repo URL, we know its name and organization. We can use that data to call the GitHub API and find out more about that repository.

This issue can be broken into multiple tasks for pairing:

• Add a Lambda function and API route called GetRepoData
• Add the API call in the GetRepoData function to return information about the repo, such as number of open issues, whether it has recent activity, etc.
• Display the data in the RepoTable component in the frontend