HBX-2963 Move gpg signing to a release profile

pom.xml

@@ -351,11 +351,6 @@
             </plugins>
         </pluginManagement>
         <plugins>
-            <!-- Skip the deploy plugin explicitly: we use nexus-staging-maven-plugin instead -->
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-gpg-plugin</artifactId>
-            </plugin>
             <!-- Skip the deploy plugin explicitly: we use nexus-staging-maven-plugin instead -->
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
@@ -393,6 +388,24 @@
     </build>
 
     <profiles>
+        <profile>
+            <id>release</id>
+            <activation>
+                <property>
+                    <name>performRelease</name>
+                    <value>true</value>
+                </property>
+            </activation>
+            <build>
+                <plugins>
+                    <plugin>
+                        <groupId>org.apache.maven.plugins</groupId>
+                        <artifactId>maven-gpg-plugin</artifactId>
+                    </plugin>
+                </plugins>
+            </build>
+        </profile>
+
         <!--
              WARNING: this MUST be the very last profile,
              so that the "report" module is the very last module,