added support for updating ACL on endpoint

Added the support of providing a JSON file for updating the ACL on an endpoint. Format of the file content to be :

```json
{
  "Rules": [
    {
      "Order": "0",
      "Action": "permit",
      "RemoteSubnet": "10.0.0.0/24",
      "Description": "Subnet1"
    },
    {
      "Order": "1",
      "Action": "permit",
      "RemoteSubnet": "10.0.1.0/24",
      "Description": "Subnet2"
    }
  ]
}
```