[Proposal] Add Support for profiles

[Armaldio]

The command line could support profiles config files

This could work as follow:

config.js
config.dev.js
config.prod.js
config.custom.js

config.js

module.exports = {
	"electron": "6.0.1",
	...
}

config.dev.js

module.exports = {
	"electron": "6.0.1",
	"window": {	
	    "fullscreen": false, // no fullscreen on dev
	},
	...
}

config.prod.js

module.exports = {
	"electron": "6.0.1",
	"developer": {
    	"showConstructDevTools": false, // no devtools on prod
	},
	"window": {	
	    "fullscreen": true, // fullscreen on prod
	},
	...
}

config.custom.js

module.exports = {
	"electron": "5.0.0", // custom electron version
	...
}

Then you can specify profile on command:

$ efc build -p custom

That will merge config.js with config.custom.js

$ efc build -p dev

That will merge config.js with config.dev.js