Consider changing how the layout is defined

[jwoertink]

Per @paulcsmith

I would have expected this to be the name of the file and not the folder. May be worth changing this so the default is always src/emails/templates/layouts/{file} and the layout is the name of the file, not the folder. I think that is more common in most languages and that way you have one folder with all your layouts rather than a folder for each kind of layout

In reference to specifying a layout like layout my_email_layout