[CLI Generator] Initial functionality

[joshuapease]

Overview

Helps cut down on busywork and stick to team standards.

We're calling this a generator to line up with Yii/Gii naming conventions.

Core Features

• Can create partials / w corresponding parts-kit files
• Can create a basic template with example "best practices"
• Can reference a section handle and create corresponding templates for each entryType

Stretch Goals

• Can create an section and entryTypes via the CLI (optionally create templates too) [CLI Generator] Create Sections & Entrytypes via the CLI #38