webopi.warproduct: Remove databrowser2.rap plugin

When included, its RedirectServlet would route all requests to "/d", the
tandalone databrowser. "/w", "/m" for *.opi access was no longer
possible. Without the databrowser2.rap plugin, the webopi.war starts as
a WebOPI for *.opi files, but still includes the "New Data Browser Plot"
button in the toolbar.