Sweep node wallet handler #72

Given I am using server "localhost"
    And I set "Content-Type" header to "application/json"
    And I set variable "destination_address" as "ak_<destinatgion>"
    When I make a POST request to path "/secrets/sweep" with data
"""
{
  "auth_token": "{{node_password}}",
   "destination_address": "ak_..."
}
"""
    Then the response must be 200
    Then the balance at "{{node_address}}" must be 0