Moved the Cornerstone viewport code to an extension. Tons of changes to rollup and package.json files to make everything play nicely

Packages-react/extensions/ohif-cornerstone-extension/.babelrc

@@ -0,0 +1,14 @@
+{
+  "presets": [
+    ["@babel/preset-env", {
+      "targets": {
+        "ie": "11"
+      }
+    }],
+    "@babel/preset-react"
+  ],
+  "plugins": [
+    "@babel/plugin-proposal-class-properties",
+    "@babel/plugin-transform-runtime"
+  ]
+}