Remove all code-templates but the copyright header and make that generic

[HannesWell]

Create a parameterized copyright header according to: https://www.eclipse.org/projects/handbook/#ip-copyright-headers

The new copyright template is:

/********************************************************************************
 * Copyright (c) ${year}, ${year} ${user} and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *   ${user} - initial API and implementation
 ********************************************************************************/