Revert "Build JavaMail inline"

This reverts commit 3621c938a9.

app/src/main/java/javax/mail/Version.java

@@ -1,26 +0,0 @@
-/*
- * Copyright (c) 1997, 2019 Oracle and/or its affiliates. All rights reserved.
- *
- * This program and the accompanying materials are made available under the
- * terms of the Eclipse Public License v. 2.0, which is available at
- * http://www.eclipse.org/legal/epl-2.0.
- *
- * This Source Code may also be made available under the following Secondary
- * Licenses when the conditions for such availability set forth in the
- * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
- * version 2 with the GNU Classpath Exception, which is available at
- * https://www.gnu.org/software/classpath/license.html.
- *
- * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
- */
-
-package javax.mail;
-
-/**
- * Package-private class that defines the version of Jakarta Mail.
- * This file is a template for the class that is generated
- * at build time.
- */
-class Version {
-    public static final String version = "1.6.5-SNAPSHOT";
-}