Remove broken and dead tutorial links

[pavan-rangani]

Summary

• Remove hackhands.com Instagram Clone tutorial link -- the domain now redirects to the Pluralsight homepage with no trace of the original content
• Remove discoversdk.com Angular 5 ToDo App links (2 links) -- the site has an invalid SSL certificate making it completely unreachable
• Remove scotch.io tutorial links (3 links) -- Scotch.io was acquired by DigitalOcean, and these specific tutorial pages now return HTTP 410 (Gone) or 404 errors:
  • "Build a Twitter Stream with React and Node"
  • "Build a real-time Markdown Editor with NodeJS"
  • "Build a Blog with Vue, GraphQL and Apollo"
• Remove ScotchIO from Additional Resources section since the domain is no longer active

Verification

Each link was individually tested and confirmed to be inaccessible:

• hackhands.com -> 301 to pluralsight.com/hackhands (generic homepage, original content gone)
• discoversdk.com -> ERR_TLS_CERT_ALTNAME_INVALID
• scotch.io/tutorials/* -> 301 to digitalocean.com/community/tutorials/* -> HTTP 410/404

[BenBE]

Are the old URLs available on archive.org by chance?

[pavan-rangani]

Great question! I checked all the removed URLs on the Wayback Machine:

Available on archive.org:

• hackhands.com/building-instagram-clone-angularjs-satellizer-nodejs-mongodb/ — https://web.archive.org/web/2023/https://hackhands.com/building-instagram-clone-angularjs-satellizer-nodejs-mongodb/
• scotch.io tutorials:
  • https://web.archive.org/web/2023/https://scotch.io/tutorials/build-a-real-time-twitter-stream-with-node-and-react-js
  • https://web.archive.org/web/2023/https://scotch.io/tutorials/building-a-real-time-markdown-viewer
  • https://web.archive.org/web/2023/https://scotch.io/tutorials/build-a-blog-with-vue-graphql-and-apollo-client

Not available on archive.org:

• discoversdk.com links — no usable snapshots found

Would you prefer I update the PR to replace the working links with their archive.org URLs instead of removing them, and only remove the discoversdk.com ones that have no archived version?

[BenBE]

It doesn't hurt to keep those links (replaced by the archive copies) if reasonable archival versions of the page exist.

For the discoversdk.com links it's sad that there's no copy, but can't be helped. Drop those.

[github-actions]

This pull request has been automatically marked as stale because it has had no activity in 90 days. It will be closed in 30 days if no further activity occurs. If it's still relevant, rebasing or leaving a comment will keep it open -- thank you for the contribution!