JBDS-3187 Check BUILD_ALIAS with standard property enforcer rule.

Also removed custom rules and custom module - if we get more complex rules one day we can
add it back, but should be external since otherwise the parent pom and the rules will have a cyclic dependency.

Tested by using:
mvn -Dtycho.mode=maven verify -DBUILD_ALIAS=<value>

CR1 (pass)
CR1a (pass)
     (fail - must be specified)
Final (fail - Final is not allowed)

Two cases are allowed in even though properly not proper:
CR (passes, but should fail since it needs a number)
GA1a (passes, but there should not be multiple GA's nor respins)

But this at least catches the most important one - not having Final in the name.

pom.xml

@@ -14,7 +14,6 @@
   <name>JBDS - Product, Installers</name>
   <packaging>pom</packaging>
   <modules>
-    <module>rules</module>
     <module>plugins</module>
     <module>features</module>
     <module>site</module>
@@ -51,23 +50,24 @@
       <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-enforcer-plugin</artifactId>
-          <version>1.0-beta-1</version>
-          <dependencies>
-              <dependency>
-                  <groupId>com.jboss.devstudio</groupId>
-                  <artifactId>ParentPomVersionCheckRule</artifactId>
-                  <version>0.1</version>
-              </dependency>
-          </dependencies>
+          <version>1.3.1</version>
           <executions>
               <execution>
-                  <id>enforce</id>
-                  <configuration><rules>
-                        <ParentPomVersionCheckRule implementation="com.jboss.devstudio.enforcer.rule.ParentPomVersionCheckRule"><shouldIfail>true</shouldIfail></ParentPomVersionCheckRule>
-                  </rules></configuration>
-                  <goals>
-                      <goal>enforce</goal>
-                  </goals>
+                  <id>enforce-properversion</id>
+		  <goals>
+		    <goal>enforce</goal>
+		  </goals>
+                  <configuration>
+		    <rules>
+                        <requireProperty>
+			  <property>BUILD_ALIAS</property>
+			  <message>BUILD_ALIAS is missing, it must be specificed.</message>
+			  <regex>.*(Alpha|Beta|CR|GA)\d?[a-z]?</regex>
+			  <regexMessage>The BUILD_ALIAS (${BUILD_ALIAS}) is invalid. Must contain either Alpha, Beta, CR or GA + optional postfix.</regexMessage>
+			</requireProperty>
+                  </rules>
+		  <fail>true</fail>
+		  </configuration>
               </execution>
           </executions>
       </plugin>