build: pre-build script

The pre-build scripts does the following:
1. Downloads the documentation from electron/electron and data/blog
   from electron/electronjs.org
2. Moves the files to the right folders based on the contents of
   `docs-reorg.json`
3. Add frontmatter to each file
4. Fixes internal links and multiline image titles
5. Generates the sidebar using the folder structure

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Fix #6
Ref: Solves parts of #2

.gitignore

@@ -1,3 +1,8 @@
 node_modules
 .docusaurus
 .DS_Store
+content/
+docs/
+blog/
+package-lock.json
+sidebars.js

.prettierrc

@@ -0,0 +1,3 @@
+{
+  "singleQuote": true
+}

.vscode/launch.json

@@ -0,0 +1,17 @@
+{
+  // Use IntelliSense to learn about possible attributes.
+  // Hover to view descriptions of existing attributes.
+  // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "type": "pwa-node",
+      "request": "launch",
+      "name": "Launch Program",
+      "skipFiles": ["<node_internals>/**"],
+      "program": "${workspaceFolder}/scripts/pre-build.js",
+      "console": "integratedTerminal",
+      "cwd": "${workspaceFolder}"
+    }
+  ]
+}