Remove JOC Cockpit version from About box and Jetty version from Response Headers

Current Situation

• The JOC Cockpit offers an "About JS7 JobScheduler" box from the Login Screen that holds the version number and build number of JOC Cockpit.
• Any response headers of Jetty include the Jetty version number.

Desired Behavior

• The JOC Cockpit "About" box in the login screen should not display version information.
• Jetty should be configured not to send its version number with response headers by use of the jetty.send.server.version setting.

Maintainer Note

The default is true and it set in ./jetty/etc/jetty.xml. The installer set this value false.

<Set name="sendServerVersion"><Property name="jetty.httpConfig.sendServerVersion" default="false" /></Set>