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/utils/testUtils.tsx

@@ -0,0 +1,83 @@
+/**
+ * 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 {
+  ActivatablePluginDetails,
+  DownloadablePluginDetails,
+} from 'flipper-plugin-lib';
+
+export function createMockDownloadablePluginDetails(
+  params: {
+    id?: string;
+    name?: string;
+    version?: string;
+    title?: string;
+    flipperEngineVersion?: string;
+    downloadUrl?: string;
+    gatekeeper?: string;
+    lastUpdated?: Date;
+  } = {},
+): DownloadablePluginDetails {
+  const {id, version, title, flipperEngineVersion, gatekeeper, lastUpdated} = {
+    id: 'test',
+    version: '3.0.1',
+    flipperEngineVersion: '0.46.0',
+    lastUpdated: new Date(1591226525 * 1000),
+    ...params,
+  };
+  const lowercasedID = id.toLowerCase();
+  const name = params.name || `flipper-plugin-${lowercasedID}`;
+  const details: DownloadablePluginDetails = {
+    name: name || `flipper-plugin-${lowercasedID}`,
+    id: id,
+    bugs: {
+      email: 'bugs@localhost',
+      url: 'bugs.localhost',
+    },
+    category: 'tools',
+    description: 'Description of Test Plugin',
+    flipperSDKVersion: flipperEngineVersion,
+    engines: {
+      flipper: flipperEngineVersion,
+    },
+    gatekeeper: gatekeeper ?? `GK_${lowercasedID}`,
+    icon: 'internet',
+    main: 'dist/bundle.js',
+    source: 'src/index.tsx',
+    specVersion: 2,
+    pluginType: 'client',
+    title: title ?? id,
+    version: version,
+    downloadUrl: `http://localhost/${lowercasedID}/${version}`,
+    lastUpdated: lastUpdated,
+    isBundled: false,
+    isActivatable: false,
+  };
+  return details;
+}
+
+export function createMockActivatablePluginDetails(
+  base: Partial<ActivatablePluginDetails>,
+): ActivatablePluginDetails {
+  return {
+    id: 'Hello',
+    specVersion: 2,
+    isBundled: false,
+    isActivatable: true,
+    dir: '/Users/mock/.flipper/thirdparty/flipper-plugin-sample1',
+    entry: './test/index.js',
+    name: 'flipper-plugin-hello',
+    version: '0.1.0',
+    pluginType: 'client',
+    source: 'src/index.js',
+    main: 'dist/bundle.js',
+    title: 'Hello',
+    ...base,
+  };
+}