Deprecate Derby support since Apache Derby is retired

[marschall]

From the Apache Derby project site

On 2025-10-10, the Derby developers voted to retire the project into a read-only state. Derby development and bug-fixing have ended. No further releases will be published. The Derby website and wiki are frozen in place. Derby JIRA issues are now read-only and new bugs cannot be logged. The user and developer lists are disabled and can be accessed only through their archives.

The last Apache Derby release was on 14 November 2023. We should probably first deprecate and the remove Derby support. Maybe log a warning when Derby is detected.

This should probably be coordinated with Spring Framework, I raised spring-projects/spring-framework#36042.

A quick search shows the following affected code places:

• org.springframework.boot.jdbc.DatabaseDriver
• org.springframework.boot.jdbc.EmbeddedDatabaseConnection
• org.springframework.boot.devtools.autoconfigure.DevToolsDataSourceAutoConfiguration

I can work on a PR if there is agreement.

[snicoll]

We're going to deprecate it sooner than framework (due to our 6months release cadance). @marschall if you'd like to submit a PR it'd be most welcome. Let us know either way please.

[marschall]

I'll do a PR