Move app/src (mostly) to flipper-ui-core/src

Summary:
This diff moves all UI code from app/src to app/flipper-ui-core. That is now slightly too much (e.g. node deps are not removed yet), but from here it should be easier to move things out again, as I don't want this diff to be open for too long to avoid too much merge conflicts.

* But at least flipper-ui-core is Electron free :)
* Killed all cross module imports as well, as they where now even more in the way
* Some unit test needed some changes, most not too big (but emotion hashes got renumbered in the snapshots, feel free to ignore that)
* Found some files that were actually meaningless (tsconfig in plugins, WatchTools files, that start generating compile errors, removed those

Follow up work:
* make flipper-ui-core configurable, and wire up flipper-server-core in Electron instead of here
* remove node deps (aigoncharov)
* figure out correct place to load GKs, plugins, make intern requests etc., and move to the correct module
* clean up deps

Reviewed By: aigoncharov

Differential Revision: D32427722

fbshipit-source-id: 14fe92e1ceb15b9dcf7bece367c8ab92df927a70

desktop/flipper-ui-core/src/fb-stubs/constants.tsx

@@ -0,0 +1,53 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+import {DeviceOS} from 'flipper-plugin';
+
+export default Object.freeze({
+  GRAPH_APP_ID: '',
+  GRAPH_CLIENT_TOKEN: '',
+  GRAPH_ACCESS_TOKEN: '',
+
+  // this provides elevated access to scribe. we really shouldn't be exposing this.
+  // need to investigate how to abstract the scribe logging so it's safe.
+  GRAPH_SECRET: '',
+  GRAPH_SECRET_ACCESS_TOKEN: '',
+
+  // Provides access to Insights Validation endpoint on interngraph
+  INSIGHT_INTERN_APP_ID: '',
+  INSIGHT_INTERN_APP_TOKEN: '',
+
+  // Enables the flipper data to be exported through shareabale link
+  ENABLE_SHAREABLE_LINK: false,
+
+  IS_PUBLIC_BUILD: true,
+
+  FEEDBACK_GROUP_LINK: 'https://github.com/facebook/flipper/issues',
+
+  // Workplace Group ID's
+  DEFAULT_SUPPORT_GROUP: {
+    name: 'Default Support Group',
+    workplaceGroupID: 0,
+    requiredPlugins: ['Inspector'],
+    defaultPlugins: ['DeviceLogs'],
+    supportedOS: ['Android'] as Array<DeviceOS>,
+    deeplinkSuffix: 'default',
+    papercuts: '',
+  },
+
+  SUPPORT_GROUPS: [],
+
+  // Only WebSocket requests from the following origin prefixes will be accepted
+  VALID_WEB_SOCKET_REQUEST_ORIGIN_PREFIXES: [
+    'chrome-extension://',
+    'localhost:',
+    'http://localhost:',
+    'app://',
+  ],
+});