Allow custom resource names via parameters for Microsoft Azure provider

[jamesbjackson]

The reason for this request is that Microsoft has some best practise for Azure resource naming convention which can be seen here https://docs.microsoft.com/en-us/azure/architecture/best-practices/naming-conventions - So we trying to best follow this approach to naming our resources.

The issue is we can't over-ride the name currently as SparkleFormation always uses the generated name of the resource while if we use native JSON then it possible.

An example of what I am trying to archive is below. Any help to gain this functionality would be greatly appreciated, I been looking through the ruby code but not sure where best to add this functionality so could submit a PR.

{
  "$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "vnetName": {
      "type": "string",
      "metadata": {
        "description": "Unique name of the virtual network"
      }
    },
    "vnetAddressPrefix": {
      "type": "string",
      "metadata": {
        "description": "Address blocks reserved for this virtual network in CDIR notation"
      }
    }
  },
  "variables": {
    "apiVersion": "2015-06-15"
  },
  "resources": [
    {
      "apiVersion": "[variables('apiVersion')]",
      "type": "Microsoft.Network/virtualNetworks",
      "name": "[parameters('vnetName')]",
      "location": "[resourceGroup().location]",
      "properties": {
        "addressSpace": {
          "addressPrefixes": [
            "[parameters('vnetAddressPrefix')]"
          ]  
        }
      }
    }
  ]
}