Implement retrieval of authorization token for Fabric via iframe rpc (#1647)

* For Fabric, send message to get Authorization token from iframe parent

* tokenProvider: set date header and return token

* Expect account endpoint on initialize message from Fabric

* Fix format

---------

Co-authored-by: artrejo <artrejo@microsoft.com>

src/Contracts/ExplorerContracts.ts

@@ -1,46 +1,6 @@
+import { MessageTypes } from "Contracts/MessageTypes";
 import * as ActionContracts from "./ActionContracts";
 import * as Diagnostics from "./Diagnostics";
 import * as Versions from "./Versions";
 
-/**
- * Messaging types used with Data Explorer <-> Portal communication
- * and Hosted <-> Explorer communication
- */
-export enum MessageTypes {
-  TelemetryInfo,
-  LogInfo,
-  RefreshResources,
-  AllDatabases,
-  CollectionsForDatabase,
-  RefreshOffers,
-  AllOffers,
-  UpdateLocationHash,
-  SingleOffer,
-  RefreshOffer,
-  UpdateAccountName,
-  ForbiddenError,
-  AadSignIn,
-  GetAccessAadRequest,
-  GetAccessAadResponse,
-  UpdateAccountSwitch,
-  UpdateDirectoryControl,
-  SwitchAccount,
-  SendNotification,
-  ClearNotification,
-  ExplorerClickEvent,
-  LoadingStatus,
-  GetArcadiaToken,
-  CreateWorkspace,
-  CreateSparkPool,
-  RefreshDatabaseAccount,
-  CloseTab,
-  OpenQuickstartBlade,
-  OpenPostgreSQLPasswordReset,
-  OpenPostgresNetworkingBlade,
-  OpenCosmosDBNetworkingBlade,
-  DisplayNPSSurvey,
-  OpenVCoreMongoNetworkingBlade,
-  OpenVCoreMongoConnectionStringsBlade,
-}
-
-export { ActionContracts, Diagnostics, Versions };
+export { ActionContracts, Diagnostics, MessageTypes, Versions };