IDEA-104500 Gradle: Allow to reuse common logic for other external systems

Don't process orphan external modules when the project is already closed
Applied generic product name to the 'tip of the day' welcome page (actual replacement is performed at com.intellij.ide.util.TipUIUtil.openTipInBrowser())
IDEA-104500 Gradle: Allow to reuse common logic for other external systems

Perform not only 'project disposed' check on external project refresh failure but 'project open' as well