snapshot/backup docs improvement

[jerrinot]

TODO:

• figure out how to link it with reference doc at https://questdb.io/docs/reference/sql/snapshot/ - this should be improved too
• editorial changes

[github-actions]

🚀 Build success!

Latest successful preview: https://66a277822ad02d51edcdaeb6--unruffled-blackwell-31bfb2.netlify.app

Commit SHA: e5230ff

📦 Build generates a preview & updates link on each commit.

[jerrinot]

@goodroot it's ready for your pass. feel free to edit it as you see fit. the reference documentation could be more ... reference-like and the guide could use more imperative language. but I think this is still an improvement compared to the current state.

[goodroot]

Much appreciated, this is a large improvement.

Made a somewhat bold decision to deprecate the backup doc & redir to snapshot.

The main reason is to clear up the search/discovery issue.

questdb/questdb#4811

Use the deprecated BACKUP operation. Not only it's deprecated, it does not support incremental backups either.

Updated this line to point to a gist vs. the documentation.

However, is it also the case that BACKUP has been deprecated since 7.3.3?

Or is it still available today in 8.1.0?

[jerrinot]

@goodroot: thanks improving this PR!

About the BACKUP situation: Between 7.3.3(?) it was deprecated on all platforms, but Windows. From 8.1 upwards it's deprecated on all platforms, including Windows. Yet the command itself is still there and works.

[goodroot]

@jerrinot Got it - thanks for confirming.