fixed bad duplications of @EnableAutoConfiguration exclude (and
@Import); thanks
https://github.com/spring-projects/spring-boot/issues/1328.  Also
renamed classes, and other minor adjustments - verified that
SpringBootServerLoginTest is green and tomcatRunWAR still/again works.
Also killed DataSourceConfigurationTest, as it’s failing (with “At least
one JPA metamodel must be present”), and doesn’t really add any value
anymore - the higher-level SpringBootServerLoginTest covers more better.

Signed-off-by: Michael Vorburger <mike@vorburger.ch>