[bs-127] Add DataSourceTransactionManager if no others are in use

* If the auto config class has a high Order it can check for
an existing transaction manager
* Unit tests added, and checked also witrh petclinic

[Fixes #50064347]

spring-bootstrap-samples/spring-bootstrap-actuator-sample/pom.xml

@@ -95,16 +95,6 @@
 			<groupId>org.springframework.security</groupId>
 			<artifactId>spring-security-javaconfig</artifactId>
 		</dependency>
-		<dependency>
-			<groupId>org.apache.tomcat</groupId>
-			<artifactId>tomcat-jdbc</artifactId>
-		</dependency>
-		<dependency>
-			<groupId>mysql</groupId>
-			<artifactId>mysql-connector-java</artifactId>
-			<version>5.1.23</version>
-			<scope>runtime</scope>
-		</dependency>
 	</dependencies>
 	<build>
 		<plugins>