Document the supported Liquibase bootstrap for jdbc:libsql: URLs #262

Goal

Document, and cover with a test, how to point Liquibase at a jdbc:libsql:http(s)://... URL: pass the driver class explicitly (io.github.magnusp.libsql.jdbc.LibsqlDriver) or hand Liquibase a DataSource.

Why

Liquibase resolves a JDBC driver class from the URL before it opens a connection. DatabaseFactory.findDefaultDriver only consults registered liquibase.database.Database implementations, and SQLiteDatabase.getDefaultDriver claims only:

• jdbc:sqlite: -> org.sqlite.JDBC

So:

• DatabaseFactory.openDatabase("jdbc:libsql:http://...") fails with Driver class was not specified and could not be determined from the url (jdbc:libsql:...).
• The jdbc:sqlite: alias resolves to xerial's driver class, which is not on the classpath (and would open a local file, not sqld).

This is not fixable inside the driver, because Liquibase never asks DriverManager which driver accepts the URL. It is a configuration and documentation gap. Pinned by LiquibaseIT#databaseFactoryCannotResolveALibsqlUrlToADriver in #257.

Workarounds that work today

• API: new JdbcConnection(DriverManager.getConnection(url)) plus new SQLiteDatabase(). The SQLiteDatabase part disappears once the product-name issue is fixed.
• Liquibase Maven plugin or liquibase.properties: set the driver class, driver=io.github.magnusp.libsql.jdbc.LibsqlDriver.
• Spring Boot or any pool: pass a DataSource and set spring.datasource.driver-class-name=io.github.magnusp.libsql.jdbc.LibsqlDriver.

Where

• Add a Liquibase section to docs/ (or extend README.md) with the three configurations above.
• Add a positive LiquibaseIT case that uses DatabaseFactory.openDatabase(url, null, null, LibsqlDriver.class.getName(), null) and asserts the result is a SQLiteDatabase. This depends on Report database product name as exactly SQLite so dialect detection works #261.
• Keep the negative pin until then.

Verification

• The documented snippets run against the pinned sqld container.
• ./mvnw -pl libsql-jdbc -am verify -Dit.test=LiquibaseIT
• ./mvnw spotless:check

Found while adding the Liquibase integration tests in #257.