Add fast profile

Checkstyle and animal sniffer takes a significant amount of time when
building the project.

Add a "fast" profile that flips the `disable.checks` property. Can be
enabled either via `-Pfast` or `-Ddisable.checks=true`.

See gh-3928

spring-boot-parent/pom.xml

@@ -19,6 +19,7 @@
 	</organization>
 	<properties>
 		<main.basedir>..</main.basedir>
+		<disable.checks>false</disable.checks>
 		<java.version>1.6</java.version>
 		<aether.version>1.0.2.v20150114</aether.version>
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
@@ -438,6 +439,7 @@
 						<id>checkstyle-validation</id>
 						<phase>validate</phase>
 						<configuration>
+							<skip>${disable.checks}</skip>
 							<configLocation>src/checkstyle/checkstyle.xml</configLocation>
 							<suppressionsLocation>src/checkstyle/checkstyle-suppressions.xml</suppressionsLocation>
 							<headerLocation>src/checkstyle/checkstyle-header.txt</headerLocation>
@@ -562,6 +564,7 @@
 				<groupId>org.codehaus.mojo</groupId>
 				<artifactId>animal-sniffer-maven-plugin</artifactId>
 				<configuration>
+					<skip>${disable.checks}</skip>
 					<signature>
 						<groupId>org.codehaus.mojo.signature</groupId>
 						<artifactId>java16</artifactId>
@@ -638,6 +641,63 @@
 				</pluginRepository>
 			</pluginRepositories>
 		</profile>
+		<profile>
+			<id>fast</id>
+			<activation>
+				<property>
+					<name>fast</name>
+				</property>
+			</activation>
+			<properties>
+				<disable.checks>true</disable.checks>
+			</properties>
+			<repositories>
+				<repository>
+					<id>spring-ext</id>
+					<url>http://repo.spring.io/ext-release-local/</url>
+					<releases>
+						<enabled>true</enabled>
+					</releases>
+					<snapshots>
+						<enabled>false</enabled>
+					</snapshots>
+				</repository>
+				<repository>
+					<id>spring-milestones</id>
+					<name>Spring Milestones</name>
+					<url>http://repo.spring.io/milestone</url>
+					<snapshots>
+						<enabled>false</enabled>
+					</snapshots>
+				</repository>
+				<repository>
+					<id>spring-snapshots</id>
+					<name>Spring Snapshots</name>
+					<url>http://repo.spring.io/snapshot</url>
+					<snapshots>
+						<enabled>true</enabled>
+					</snapshots>
+				</repository>
+			</repositories>
+			<pluginRepositories>
+				<pluginRepository>
+					<id>spring-milestones</id>
+					<name>Spring Milestones</name>
+					<url>http://repo.spring.io/milestone</url>
+					<snapshots>
+						<enabled>false</enabled>
+					</snapshots>
+				</pluginRepository>
+				<pluginRepository>
+					<id>spring-snapshots</id>
+					<name>Spring Snapshots</name>
+					<url>http://repo.spring.io/snapshot</url>
+					<snapshots>
+						<enabled>true</enabled>
+					</snapshots>
+				</pluginRepository>
+			</pluginRepositories>
+		</profile>
 		<profile>
 			<id>eclipse.profile</id>
 			<activation>