update target platform to include jetty 9.4.6 (CVE issue)

Fedora and RHEL have updated to Jetty 9.4.6 due to this CVE:

• https://bugzilla.redhat.com/show_bug.cgi?id=1464158

Currently, JBT/devstudio target platform includes Jetty 9.4.5, as that's what was in Oxygen.0.RC4.

But we could move to a newer version if we want to have the same version in linux and in windows/OSX versions of JBT/devstudio.

Affected manifest files (which require jetty bundles from [9.4.0,9.5.0))

• [1] ./jbosstools-aerogear/cordovasim/plugins/org.jboss.tools.cordovasim.eclipse/META-INF/MANIFEST.MF
• [2] ./jbosstools-aerogear/cordovasim/plugins/org.jboss.tools.cordovasim/META-INF/MANIFEST.MF
• [3] ./jbosstools-aerogear/cordovasim/tests/org.jboss.tools.cordovasim.eclipse.test/META-INF/MANIFEST.MF
• [4] ./jbosstools-base/foundation/tests/org.jboss.tools.foundation.core.test/META-INF/MANIFEST.MF
• [5] ./jbosstools-browsersim/plugins/org.jboss.tools.browsersim.ui/META-INF/MANIFEST.MF
• [6] ./jbosstools-central/central/tests/org.jboss.tools.central.test/META-INF/MANIFEST.MF
• [7] ./jbosstools-livereload/plugins/org.jboss.tools.livereload.core/META-INF/MANIFEST.MF
• [8] ./jbosstools-livereload/tests/org.jboss.tools.livereload.test/META-INF/MANIFEST.MF
• [9] ./jbosstools-server/jmx/tests/org.jboss.tools.jmx.jolokia.test/META-INF/MANIFEST.MF