Add Security Manager mention when running JMeter in distributed environment

Cherry-pick from commits 5ca8729b9acdc4f3e7ab603071d9f783a311ad1a and 69c1109d4ca2ad6495470c4ed4f423626b4e57bc from master branch  on update-docs-v5.5-release branch, rebuild of documentation, and copy the result files on asf-site branch (jmeter-site repo)
diff --git a/security.html b/security.html
index 1389d99..668566b 100644
--- a/security.html
+++ b/security.html
@@ -195,6 +195,15 @@
     evaluate untrusted jmx files, it is up to you to provide the
     required isolation.
   </p>
+                  
+                <p>
+                        Still in the area of security, when JMeter is used in distributed
+    environment, we recommend setting up the security manager in order
+    to avoid any execution of malicious code on the distributed
+    architecture. See the <a href="./usermanual/remote-test.html#security-manager">
+    Security-Manager documentation</a> for its implementation.
+  
+                </p>
                 
             </div>
             <div class="section">