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/mkdirs/index.js

@@ -0,0 +1,14 @@
+'use strict'
+const u = require('universalify').fromPromise
+const { makeDir: _makeDir, makeDirSync } = require('./make-dir')
+const makeDir = u(_makeDir)
+
+module.exports = {
+  mkdirs: makeDir,
+  mkdirsSync: makeDirSync,
+  // alias
+  mkdirp: makeDir,
+  mkdirpSync: makeDirSync,
+  ensureDir: makeDir,
+  ensureDirSync: makeDirSync
+}