feat(proxy datasource): JSON server configuration launch (#2791)

* feat: delegating dicom web proxy datasource

* fix: configurably allow WADO image loader to issue preflight OPTIONS request

* Added documentation and fixed up some error handling from PR review

* review comments changes

* another small code review fix

platform/viewer/public/config/default.js

@@ -53,6 +53,14 @@ window.config = {
         useBulkDataURI: false,
       },
     },
+    {
+      friendlyName: 'dicomweb delegating proxy',
+      namespace: '@ohif/extension-default.dataSourcesModule.dicomwebproxy',
+      sourceName: 'dicomwebproxy',
+      configuration: {
+        name: 'dicomwebproxy',
+      },
+    },
     {
       friendlyName: 'dicom json',
       namespace: '@ohif/extension-default.dataSourcesModule.dicomjson',