refactor(init): share common files between templates (#5315)

* Create shared folder & update init logic

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Restore needed links

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Prevent copying symlinks

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Reuse some FB files

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Minor tweak

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Minor refactors

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Fix bootstrap url

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Add path alias

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Handle facebook template more gracefully

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* minor refactor: extract getTypeScriptBaseTemplate

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

packages/docusaurus-init/templates/shared/sidebars.js

@@ -0,0 +1,26 @@
+/**
+ * Creating a sidebar enables you to:
+ - create an ordered group of docs
+ - render a sidebar for each doc of that group
+ - provide next/previous navigation
+
+ The sidebars can be generated from the filesystem, or explicitly defined here.
+
+ Create as many sidebars as you want.
+ */
+
+module.exports = {
+  // By default, Docusaurus generates a sidebar from the docs folder structure
+  tutorialSidebar: [{type: 'autogenerated', dirName: '.'}],
+
+  // But you can create a sidebar manually
+  /*
+  tutorialSidebar: [
+    {
+      type: 'category',
+      label: 'Tutorial',
+      items: ['hello'],
+    },
+  ],
+   */
+};