Find a way to update renamed notebook — instead of creating a new one & deleting old one like now

[hectorperez]

We call UserNotebooksSyncWorker every day for every user.

When a notebook title or path is changed, it creates the notebook again and deletes the old one instead of updating it.

If we do this:

• We could add comments under each notebook, stars, etc. — after we do Log in with GitHub #127
• Get first commit date from GitHub #156 wouldn't be so necessary

[hectorperez]

This may help:

When a user or org has been renamed, and you go to an old notebook URL [1], GitHub redirects to the new one [2].

Yet, [3] does not redirect to [4].

[1] https://github.com/pryde/nabp/blob/e015368c197d579c9f11fb2daf32898b7cb8ab6e/notebook/exploration.livemd
[2] https://github.com/chasebussey/nabp/blob/e015368c197d579c9f11fb2daf32898b7cb8ab6e/notebook/exploration.livemd
[3] https://github.com/pryde
[4] https://github.com/chasebussey

[hectorperez]

I opened a discussion on Livebook's about unique identifiers for notebooks livebook-dev/livebook#2585