Simple jdbc example

[Paultagoras]

Summary

This updates the JDBC example to use more generic JDBC methods.

Checklist

Delete items not relevant to your PR:

• Closes issue
• Unit and integration tests covering the common scenarios were added
• A human-readable description of the changes was provided to include in CHANGELOG
• For significant changes, documentation in https://github.com/ClickHouse/clickhouse-docs was updated with further explanations or tutorials

[mshustov]

@chernser @Paultagoras @laeg Do we want to have snippets from https://clickhouse.com/docs/en/integrations/java/jdbc-driver as runnable examples?

[sonarqubecloud]

Quality Gate failed

Failed conditions
38.5% Coverage on New Code (required ≥ 80%)
5.3% Duplication on New Code (required ≤ 3%)
C Reliability Rating on New Code (required ≥ A)

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