Oject-10438 Add Java EPC encoder and Saxon-HE extension function

Add three Java source files that enable SGTIN-96 EPC generation
directly from within the DELIVERY.xsl transformation:

- Gs1EpcEncoder.java: encodes SGTIN-96 (38-bit serial via MD5) and
  SGTIN-198 (140-bit ASCII serial); serial derived from MD5(DOCNUM+POSNR+counter)
- Sgtin96Function.java: Saxon-HE ExtensionFunctionDefinition that
  registers gs1:encodeSgtin96FromIdoc() for use in XSLT
- TransformAndEncode.java: Saxon s9api runner that registers the
  extension and executes DELIVERY.xsl in a single pass

Also update .gitignore to track java/src/ while continuing to exclude
compiled output in java/bin/.

.gitignore

@@ -19,6 +19,9 @@ dist/
 # Package files
 *.jar
 
+# additional Libraries
+libs/
+
 # Maven
 target/
 dist/
@@ -47,7 +50,9 @@ Thumbs.db
 *.flv
 *.mov
 *.wmv
+*.script
 
 test0001.camel.yaml
 testing/
 .continue/agents/new-config.yaml
+java/bin/