SpringBoot Provide a configuration property for the driverClassName of the Liquibase DataSource

Fixes gh-23810

Comment From: wilkinsona

Thanks very much for the PR, @evgeniycheban. I've squeezed this into 2.4. While I was checking to see if an update to the documentation was needed, I was reminded that we fall back to the equivalent spring.datasource.* property for the Liquibase-specific url, username, and password properties so I've polished the proposal to do the same for driver-class-name.