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/index.js

@@ -0,0 +1,16 @@
+'use strict'
+
+module.exports = {
+  // Export promiseified graceful-fs:
+  ...require('./fs'),
+  // Export extra methods:
+  ...require('./copy'),
+  ...require('./empty'),
+  ...require('./ensure'),
+  ...require('./json'),
+  ...require('./mkdirs'),
+  ...require('./move'),
+  ...require('./output-file'),
+  ...require('./path-exists'),
+  ...require('./remove')
+}