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

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

platform/viewer/package.json

@@ -57,7 +57,6 @@
     "@ohif/ui": "^2.0.0",
     "@types/react": "^16.0.0",
     "classnames": "^2.2.6",
-    "config-point": "^0.3.4",
     "core-js": "^3.16.1",
     "cornerstone-math": "^0.1.9",
     "cornerstone-tools": "6.0.2",