Add support to enable/disable Smart Away

[mjmeli]

While looking into how to control Smart Away's enablement via automations in Home Assistant, it looks like it is possible to control this, although its not supported yet. While it's presented as a scene in the app, it is more of a toggle switch. I'm dropping my findings here for now.

Enable request

{
    "Body": {
        "AwayStatus": {
            "href": "/system/away/1/status",
            "EnabledState": "Enabled"
        }
    },
    "CommuniqueType": "UpdateRequest",
    "Header": {
        "Url": "/system/away/1/status"
    }
}

Disable request

{
    "Body": {
        "AwayStatus": {
            "href": "/system/away/1/status",
            "EnabledState": "Disabled"
        }
    },
    "CommuniqueType": "UpdateRequest",
    "Header": {
        "Url": "/system/away/1/status"
    }
}

The Bridge responds similar to the below

{
	'AwayStatus': {
		'href': '/system/away/1/status',
		'EnabledState': 'Disabled',
		'ActiveState': 'Inactive'
	}
}

Subscribe

{
    "CommuniqueType": "SubscribeRequest",
    "Header": {
        "Url": "/system/away/1/status"
    }
}

The notification matches the Bridge response to the request.