Use HikariCP is jdbc and jpa starters

This commit is a companion of what was done in #6013. As HikariCP is
now the default connection pool, the jdbc and jpa starters no longer
provide `tomcat-jdbc`, but rather `HikariCP`.

Closes gh-9392

spring-boot-starters/spring-boot-starter-jdbc/pom.xml

@@ -23,8 +23,8 @@
 			<artifactId>spring-boot-starter</artifactId>
 		</dependency>
 		<dependency>
-			<groupId>org.apache.tomcat</groupId>
-			<artifactId>tomcat-jdbc</artifactId>
+			<groupId>com.zaxxer</groupId>
+			<artifactId>HikariCP</artifactId>
 		</dependency>
 		<dependency>
 			<groupId>org.springframework</groupId>

spring-boot-starters/spring-boot-starter-jdbc/src/main/resources/META-INF/spring.provides

@@ -1 +1 @@
-provides: spring-jdbc,spring-tx,tomcat-jdbc
+provides: spring-jdbc,spring-tx,HikariCP