Apply animal sniffer to entire build

Move animal sniffer configuration out of spring-boot-dependencies to
spring-boot-parent and apply it to all projects.

See gh-716

spring-boot-tools/spring-boot-loader-tools/pom.xml

@@ -128,6 +128,14 @@
 					</archive>
 				</configuration>
 			</plugin>
+			<plugin>
+				<groupId>org.codehaus.mojo</groupId>
+				<artifactId>animal-sniffer-maven-plugin</artifactId>
+				<configuration>
+					<!-- The use of SignalUtils seems to mess up animal sniffer -->
+					<skip>true</skip>
+				</configuration>
+			</plugin>
 		</plugins>
 	</build>
 </project>