Implement /package upload with URL endpoint

[chloehumphrey]

Implement the 'upload package with URL' feature to the API. Use example post request from the OpenAPI specification.

• If applicable, convert npm link to GitHub link (use code from Phase 1)
• Download the GitHub package as a zip file
• Get name and version from package.json
• Encode zip file to base 64
• Add the package to the database

[chloehumphrey]

Great work so far! 🎊 We just need to make sure we're not making assumptions about the default branch and correctly handling npm links.

• [ ] Make sure that the correct information is being used when normalizing npm links.
  • Will's code from phase 1 shows how to correctly extract the repository information
• [ ] Use octokit or the GitHub rest API with the github repository information to find the default branch
  • [ ] Replace 'master' with the correct default branch when normalizing
• [ ] Add some more error handling for when the axios calls fail