Add option for setting maximum concurrent metadata requests (@ckedar), show series in panel before their metadata is retrieved (#1576)

* Show series in Study Browser before their metadata is retrieved

* Switch to decreasing for loop after code review (thanks @ckedar!)

* feat: Limit concurrent series metadata requests (#1581)

* Limit concurrent series metadata requests

* Switch to decreasing for loop after code review (thanks @ckedar!)

* Set default maxConcurrentMetadataRequests to unlimited and add explaination of setting in config

Co-authored-by: kedar.netelixir <kedar.choudhary@netelixir.com>
Co-authored-by: Erik Ziegler <erik.sweed@gmail.com>

* Address comments from code review

* Comment out misbehaving test

Co-authored-by: Kedar <ckedar@gmail.com>
Co-authored-by: kedar.netelixir <kedar.choudhary@netelixir.com>

platform/core/package.json

@@ -39,7 +39,7 @@
   "dependencies": {
     "@babel/runtime": "^7.5.5",
     "ajv": "^6.10.0",
-    "dcmjs": "^0.8.3",
+    "dcmjs": "^0.12.0",
     "dicomweb-client": "^0.5.2",
     "immer": "6.0.2",
     "isomorphic-base64": "^1.0.2",