feat: search options (#540)

* feat: search options

* feat: sanitize folder names

* fix: add cursor: pointer to switch

* fix: explicitly make the search bar a text input

* refactor: remove magic number

* refactor: extract Switch component to its own file

* refactor: split AppState into multiple files

* refactor: review comments

webpack.dev.js

@@ -1,4 +1,4 @@
-const merge = require('webpack-merge');
+const { merge } = require('webpack-merge');
 const config = require('./webpack.config.js');
 const HtmlWebpackPlugin = require('html-webpack-plugin');