Automatically link from plugin list screen to plugin settings screens

If a plugin implements a screen for administrating its settings that
is available under "#/x/<plugin-name>/settings" it is automatically
linked from the plugin list screen.

This avoids that each plugin has to register an own menu entry for its
settings screen.

Change-Id: I6d76f5286c936fd412572e484ee45edeb176a98e
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>

gerrit-gwtui/src/main/java/com/google/gerrit/client/admin/AdminConstants.java

@@ -110,8 +110,10 @@ public interface AdminConstants extends Constants {
   String plugins();
   String pluginEnabled();
   String pluginDisabled();
+  String pluginSettingsToolTip();
 
   String columnPluginName();
+  String columnPluginSettings();
   String columnPluginVersion();
   String columnPluginStatus();