refactor: 💡 Move DICOMSR code to @ohif/core project (#1310)

* Move DICOMSR to @ohif/core

* refactor: 💡 Move DICOMSR code to @ohif/core project

We've just merged support for DICOM Structured Reports. Today, support
for this feature lives in the @ohif/viewer project in it's lib folder.
Ideally, it should be moved to @ohif/core and given a clear public API
and unit tests.

Closes: #1282

* Update imports

* CR Update: Update imports

platform/core/package.json

@@ -39,6 +39,7 @@
   "dependencies": {
     "@babel/runtime": "^7.5.5",
     "ajv": "^6.10.0",
+    "dcmjs": "^0.8.3",
     "dicomweb-client": "^0.5.2",
     "isomorphic-base64": "^1.0.2",
     "lodash.clonedeep": "^4.5.0",