(PE-3401) Moved override-webserver-settings! tests to new namespace

This commit moves the override-webserver-settings! tests from the
jetty9-service namespace to a jetty9-service-override-webserver-settings
namespace in preparation for a larger breakup of the jetty9-service
tests to come on a later PR.  No functional changes are present in the
source code as part of the migration.
(PE-3401) Log overridden settings

This commit adds a log/info call with the name of each webserver setting
being overridden through a call to override-webserver-settings!