Expose actuator endpoints for flyway and liquibase

Update the samples to expose the relevant actuator endpoint.

Closes gh-3935

spring-boot-samples/spring-boot-sample-flyway/README.adoc

+== Spring Boot Flyway Sample
+
+This sample demonstrates the flyway auto-configuration support.
+
+You can look at the `/flyway` endpoint to review the list of scripts executed.
+E.g: http//localhost:8080/flyway

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

@@ -19,10 +19,18 @@
 		<main.basedir>${basedir}/../..</main.basedir>
 	</properties>
 	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-actuator</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-data-jpa</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-web</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>org.flywaydb</groupId>
 			<artifactId>flyway-core</artifactId>

spring-boot-samples/spring-boot-sample-liquibase/README.adoc

+== Spring Boot Liquibase Sample
+
+This sample demonstrates the liquibase auto-configuration support.
+
+You can look at the `/liquibase` endpoint to review the list of scripts executed.
+E.g: http//localhost:8080/liquibase

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

@@ -19,10 +19,18 @@
 		<main.basedir>${basedir}/../..</main.basedir>
 	</properties>
 	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-actuator</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-jdbc</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-web</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>org.liquibase</groupId>
 			<artifactId>liquibase-core</artifactId>