Polish dependency management

- Remove dependency management for projects that Boot does not have a
  runtime dependency upon
- Provide dependency management for all of Spring Batch’s modules

spring-boot-autoconfigure/pom.xml

@@ -273,10 +273,5 @@
 			<artifactId>slf4j-jdk14</artifactId>
 			<scope>test</scope>
 		</dependency>
-		<dependency>
-			<groupId>org.springframework.plugin</groupId>
-			<artifactId>spring-plugin-core</artifactId>
-			<scope>test</scope>
-		</dependency>
 	</dependencies>
 </project>