feat(PDF):Add PDF viewer (#2730)

Display DICOM encapsulated PDF documents in a PDF viewer.
Addressed the remaining PR comments, and am merging this.

extensions/dicom-video/src/id.js

@@ -1,7 +1,8 @@
-const id = 'org.ohif.dicom-video';
+const Name = 'dicom-video';
+const id = `org.ohif.${Name}`;
 
 export default id;
 
-const SOPClassHandlerName = 'dicom-video';
-const SOPClassHandlerId = `${id}.sopClassHandlerModule.${SOPClassHandlerName}`;
-export { SOPClassHandlerName, SOPClassHandlerId };
+const SOPClassHandlerId = `${id}.sopClassHandlerModule.${Name}`;
+
+export { Name, SOPClassHandlerId, };