Make excludeDevtools available as a user property

See gh-16701

Author: jvwilge

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/RepackageMojo.java

@@ -193,7 +193,7 @@ public class RepackageMojo extends AbstractDependencyFilterMojo {
 	 * Exclude Spring Boot devtools from the repackaged archive.
 	 * @since 1.3
 	 */
-	@Parameter(defaultValue = "true")
+	@Parameter(property = "spring-boot.excludeDevtools", defaultValue = "true")
 	private boolean excludeDevtools = true;
 
 	/**