feat(v2): official CodeSandbox support (#3717)

* feat:added support for codesandbox

* added sandbox config file

* feat:added script to generate template for codesandbox

* added examples:generate script to package.json file

* added failing path to eslintignore

* added script to eslintignore

* added cleaning feature to script

* deleted sandbox script in root

* changed comment in codesandboxscript file

* update codesandboxscript.js + revert bad package.json changes

* eslint should check codesandboxscript

Co-authored-by: slorber <lorber.sebastien@gmail.com>

examples/facebook/src/css/custom.css

@@ -0,0 +1,33 @@
+/**
+ * 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
+ */
+
+/**
+ * Any CSS included here will be global. The classic template
+ * bundles Infima by default. Infima is a CSS framework designed to
+ * work well for content-centric websites.
+ */
+
+/* You can override the default Infima variables here. */
+:root {
+  --ifm-color-primary: #25c2a0;
+  --ifm-color-primary-dark: rgb(33, 175, 144);
+  --ifm-color-primary-darker: rgb(31, 165, 136);
+  --ifm-color-primary-darkest: rgb(26, 136, 112);
+  --ifm-color-primary-light: rgb(70, 203, 174);
+  --ifm-color-primary-lighter: rgb(102, 212, 189);
+  --ifm-color-primary-lightest: rgb(146, 224, 208);
+  --ifm-code-font-size: 95%;
+}
+
+.docusaurus-highlight-code-line {
+  background-color: rgb(72, 77, 91);
+  display: block;
+  margin: 0 calc(-1 * var(--ifm-pre-padding));
+  padding: 0 var(--ifm-pre-padding);
+}