Migrate SQL Editor history from single-cluster to multi-cluster

[alexdametto]

Summary of changes

Idea behind this PR:

• having a unique history of 100 queries
• the new history array will contains object like { clusterId, query }
• migrating the old "string-only" history into the new structure

I have not add any test since the "migration" code will probably be removed in a couple of months.

⚠️ I will update this PR do to the release next week, to avoid any conflicts.

Checklist

• Link to issue this PR refers to: https://github.com/crate/cloud/issues/2607
• Relevant changes are reflected in CHANGES.md.
• Added or changed code is covered by tests.
• Required Grand Central APIs are already merged.

[joncombe]

Looks good to me, approved, but can we have a quick chat about the migration when you are back, pls? I am slightly confused how this only runs once.

[joncombe]

Ignore my question about the migration thing. I see how this works now.