doc bug 1606 - update get-started-binary (#1609)

For doc-bug 1606, update the step 5 MC start instructions to use the new
method (as documented in
https://docs.hazelcast.com/management-center/5.7/getting-started/install#binary)

---------

Co-authored-by: Anatoly Maiegov <95342781+anatoly-hazelcast@users.noreply.github.com>

Author: amandalindsay

docs/modules/getting-started/pages/get-started-binary.adoc

@@ -690,23 +690,23 @@ Mac::
 --
 [source,shell]
 ----
-management-center/bin/start.sh
+management-center/bin/hz-mc start
 ----
 --
 Linux:: 
 + 
 --
 [source,shell]
 ----
-management-center/bin/start.sh
+management-center/bin/hz-mc start
 ----
 --
 Windows:: 
 +
 --
 [source,shell]
 ----
-management-center/bin/start.bat
+management-center/bin/mc-start.cmd
 ----
 --
 ====