Add EditorConfig file to blueprints

As discussed in #1426, EditorConfig file is added to blueprints. I have set defaults for html, css, js and hbs files and they can be modified if needed. The default is 2 space indents for all of them. Please take a look.

cc @abuiles @treyhunner @ccoenen
These could be consolidated into one group like so:

[*.{js,hbs,css,html}]
indent_style = space
indent_size = 2

Keeping them in separate groups allows users to more easily override them individually, but I'm not sure how many people use separate indentation sizes for their HTML/HBS, CSS, and JS files.

Changing the number "2" four times isn't difficult so this is non an important issue.