Initial Blitz cli commands

[robdrosenberg]

Create alpha documentation for getting blitz up and running locally and cli commands.

• Highlight blitz cli commands
• Initial Blitz project setup

[flybayer]

I have an alpha guide here with everything needed for the alpha (I think): blitz-js/blitz#131

So that's a good starting point for this issue.

[coreybrown89]

@flybayer thanks - this is super helpful.