i2ptunnel: Enhance registration authentication page

- Enable form
- Switch to multipart form for getting old private key file
- Add advanced authentications
PrivateKeyFile: Add InputStream constructor for i2ptunnel

apps/i2ptunnel/java/build.xml

@@ -270,6 +270,8 @@
                 <pathelement location="build/i2ptunnel.jar" />
                 <pathelement location="build/temp-beans.jar" />
                 <pathelement location="../../../core/java/build/i2p.jar" />
+                <!-- required for multipart form handling in register.jsp -->
+                <pathelement location="../../jetty/jettylib/jetty-i2p.jar" />
             </classpath>
             <arg value="-d" />
             <arg value="../jsp/WEB-INF/classes" />
@@ -299,6 +301,8 @@
                 <pathelement location="build/i2ptunnel.jar" />
                 <pathelement location="build/temp-beans.jar" />
                 <pathelement location="../../../core/java/build/i2p.jar" />
+                <!-- required for multipart form handling in register.jsp -->
+                <pathelement location="../../jetty/jettylib/jetty-i2p.jar" />
             </classpath>
         </javac>
         <copy file="../jsp/web.xml" tofile="../jsp/web-out.xml" />

apps/i2ptunnel/java/src/net/i2p/i2ptunnel/web/Messages.java

@@ -40,6 +40,11 @@ public class Messages {
         return Translate.getString(s, o, _context, BUNDLE_NAME);
     }
 
+    /** @since 0.9.26 */
+    public String _t(String s, Object o1, Object o2) {
+        return Translate.getString(s, o1, o2, _context, BUNDLE_NAME);
+    }
+
     /** translate (ngettext)
      *  @since 0.9.7
      */