Add NOTICE file (#631)

Signed-off-by: Wouter Born <[email protected]>

NOTICE

@@ -0,0 +1,28 @@
+This content is produced and maintained by the openHAB project.
+
+* Project home: https://www.openhab.org
+
+== Declared Project Licenses
+
+This program and the accompanying materials are made available under the terms
+of the Eclipse Public License 2.0 which is available at
+https://www.eclipse.org/legal/epl-2.0/.
+
+== Source Code
+
+https://github.com/openhab/openhab-core
+
+== Copyright Holders
+
+This content contains parts derived from the Eclipse SmartHome project for which
+the copyright holders are listed at
+https://github.com/eclipse/smarthome/blob/master/NOTICE
+
+== Cryptography
+
+Content may contain encryption software. The country in which you are currently
+may have restrictions on the import, possession, and use, and/or re-export to
+another country, of encryption software. BEFORE using any encryption software,
+please check the country's laws, regulations and policies concerning the import,
+possession, or use, and re-export of encryption software, to see if this is
+permitted.