erp5_dms: Add pdf.js file required for pdf reader

Somehow two files didn't made it to the recent deploy. I am still to figure out the reason but I suspect it might be due to my recent rebase.

/reviewed-on nexedi/erp5!166

bt5/erp5_dms/SkinTemplateItem/portal_skins/erp5_dms/pdf_js/build/pdf.js.xml

+<?xml version="1.0"?>
+<ZopeData>
+  <record id="1" aka="AAAAAAAAAAE=">
+    <pickle>
+      <global name="File" module="OFS.Image"/>
+    </pickle>
+    <pickle>
+      <dictionary>
+        <item>
+            <key> <string>__name__</string> </key>
+            <value> <string>pdf.js</string> </value>
+        </item>
+        <item>
+            <key> <string>content_type</string> </key>
+            <value> <string>application/javascript</string> </value>
+        </item>
+        <item>
+            <key> <string>precondition</string> </key>
+            <value> <string></string> </value>
+        </item>
+        <item>
+            <key> <string>title</string> </key>
+            <value> <string>pdf.js</string> </value>
+        </item>
+      </dictionary>
+    </pickle>
+  </record>
+</ZopeData>

bt5/erp5_dms/SkinTemplateItem/portal_skins/erp5_dms/pdf_js/build/pdf.worker.js.xml

+<?xml version="1.0"?>
+<ZopeData>
+  <record id="1" aka="AAAAAAAAAAE=">
+    <pickle>
+      <global name="File" module="OFS.Image"/>
+    </pickle>
+    <pickle>
+      <dictionary>
+        <item>
+            <key> <string>__name__</string> </key>
+            <value> <string>pdf.worker.js</string> </value>
+        </item>
+        <item>
+            <key> <string>content_type</string> </key>
+            <value> <string>application/javascript</string> </value>
+        </item>
+        <item>
+            <key> <string>precondition</string> </key>
+            <value> <string></string> </value>
+        </item>
+        <item>
+            <key> <string>title</string> </key>
+            <value> <string>pdf.worker.js</string> </value>
+        </item>
+      </dictionary>
+    </pickle>
+  </record>
+</ZopeData>