GUACAMOLE-773: Bring license details of bundled Java dependencies up-to-date.

doc/licenses/zxing-3.4.1/NOTICE

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+Barcode4J
+Copyright 2002-2010 Jeremias Märki
+Copyright 2005-2006 Dietmar Bürkle
+
+Portions of this software were contributed under section 5 of the
+Apache License. Contributors are listed under:
+http://barcode4j.sourceforge.net/contributors.html

doc/licenses/zxing-3.4.1/README

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+ZXing Barcode Scanning Library (https://github.com/zxing/zxing/)
+----------------------------------------------------------------
+
+    Version: 3.4.1
+    From: 'ZXing authors' (https://github.com/zxing/zxing/blob/zxing-3.4.1/AUTHORS)
+    License(s):
+        Apache v2.0
+

doc/licenses/zxing-3.4.1/maven-coordinates.txt

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+com.google.zxing:core:jar:3.4.1
+com.google.zxing:javase:jar:3.4.1