Use the single type representing plugins

Summary: Use interface PluginDetails everywhere where plugins are handled and removed PluginDefinition type which was effectively a subset of PluginDetails

Reviewed By: mweststrate

Differential Revision: D21927456

fbshipit-source-id: 434ebeef955b922cc11757e78fbba8dec05f1060

desktop/app/src/plugin.tsx

@@ -101,6 +101,7 @@ export abstract class FlipperBasePlugin<
   static icon: string | null = null;
   static gatekeeper: string | null = null;
   static entry: string | null = null;
+  static isDefault: boolean;
   static bugs: {
     email?: string;
     url?: string;