`create-spectacle`: Interactive prompts

[gksander]

What?

Our initial implementation of the create-spectacle CLI tool uses flags to pass in options. This works great, but we'd like to also offer an interactive console-prompt experience. See here for more details.

The goal of this issue is to implement an interactive console prompt setup for create-spectacle so that a user workflow can look like the following:

• Run yarn create spectacle
• CLI prompts user for a project name
• CLI prompts user for a template (JS, TS, MD, One-page etc)
• CLI then generates the project and leaves a result message

[gksander]

Closed via #1195