Add links to removed obsolete sample projects.

[p-m-j]

I found it quite frustrating to be reading / watching training content that made reference to the Jetsurvey project in this repo only to find it no longer exists. I imagine this would be even more frustating for those going through learning materials alongside learning git.

[google-cla]

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[IanGClifton]

Thank you very much for adding the links!

[IanGClifton]

Rebecca, can you verify these are the right hashes/links we want to use to point people to the projects we've removed?

[riggaroo]

Thanks, LGTM! You just need to sign the CLA

[stale]

This issue has been automatically marked as stale because it has not had any recent activity. Please comment here if it is still valid so that we can reprioritize it. Thank you for your contributions.

[p-m-j]

This issue has been automatically marked as stale because it has not had any recent activity. Please comment here if it is still valid so that we can reprioritize it. Thank you for your contributions.

still valid IMHO