Revert "XX-11331:  Calling sendMessage directly instead of creating an event when not using an outbound queue"

This reverts commit 57c9dd7ce9f3e3290a6af3f339f46d17fab1640a.
Revert "XX-11331:  Allowed disabling of the outbound queue for SipClient to allow applications to use a thread pool to send outbound requests."

This reverts commit ba73bc181e2325b7ace9bf548b48c406e80a6588.