Change references of port 61616 to port 8080 in Configuring Messaging

Per customer comment[1], Configuring Message doc has references to port 61616. This is legacy 6.x content that should be updated to reflect usage of port 8080 as single port for incoming connections in EAP 7.x.

Sections requiring edits:

• 20.2 Configuring the Client [2]
• 28.1.3 Static Discovery [3]
• 29.9 Client Reconnection and Session Reattachment [4]

[1] https://access.redhat.com/documentation/en/red-hat-jboss-enterprise-application-platform/7.0/single/configuring-messaging/#comment-1110781

[2]https://access.redhat.com/documentation/en/red-hat-jboss-enterprise-application-platform/7.0/single/configuring-messaging/#configuring_the_client

[3]https://access.redhat.com/documentation/en/red-hat-jboss-enterprise-application-platform/7.0/single/configuring-messaging/#static_discovery

[4]https://access.redhat.com/documentation/en/red-hat-jboss-enterprise-application-platform/7.0/single/configuring-messaging/#messaging_client_reconnect