Remove HSQLDB dependency from Batch Starter

This commit removes HSQLDB dependency from Batch Starter as most apps
that use Spring Batch will prefer to use a RDBMS of their choice to store
batch metadata.

Additionally, explicit spring-jdbc dependency has been replaced with JDBC
Starter dependency.

See gh-6081

spring-boot-samples/spring-boot-sample-batch/pom.xml

@@ -23,6 +23,10 @@
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-batch</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>org.hsqldb</groupId>
+			<artifactId>hsqldb</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-test</artifactId>