feat: initial CLI structure

- init: create plugin boilerplate
- install: install from local path with deps
- list: show installed plugins
- validate: check manyplug.json syntax

node_modules/fs-extra/lib/json/jsonfile.js

@@ -0,0 +1,11 @@
+'use strict'
+
+const jsonFile = require('jsonfile')
+
+module.exports = {
+  // jsonfile exports
+  readJson: jsonFile.readFile,
+  readJsonSync: jsonFile.readFileSync,
+  writeJson: jsonFile.writeFile,
+  writeJsonSync: jsonFile.writeFileSync
+}