total network settings dict support

[nixjdm]

#325 and #326 are both pretty simple, and virtualbox specific (probably / at least mostly).

For this ticket I want the ability to pass a dict / json of network settings that each provider can handle intelligently, potentially. For starters, we can go with just virtualbox again. Here we could supply data that basically amounts to the vagrant code we'd end up using.

For example: the dict =

{
	"private": {
		"ip": "192.168.50.4",
		"auto_config": "false"
	},
	"public": {
		"bridge": [
			"en1: Wi-Fi (AirPort)",
			"en6: Broadcom NetXtreme Gigabit Ethernet Controller"
		]
	}
}

This actually works pretty nicely because all the config.vm.network "private_network" in ruby are simple key/value pairs.

Eventually, other providers can have their own relevant network config stored here.

This is especially useful when added to rambo.conf.