Store preferences and scrolling, refactor to useReducer

Reviewed By: priteshrnandgaonkar

Differential Revision: D26848266

fbshipit-source-id: 738d52556b9fb65ec5b5de7c727467227167b9b9

desktop/flipper-plugin/src/state/datasource/DataSource.tsx

@@ -297,6 +297,7 @@ export class DataSource<
   setFilter(filter: undefined | ((value: T) => boolean)) {
     if (this.filter !== filter) {
       this.filter = filter;
+      // TODO: this needs debouncing!
       this.rebuildOutput();
     }
   }