(SUP-3005) Update plan output format

[jarretlavallee]

This commit changes the output of the plan format to have a summary and
details. It aligns the parameters with the init.pp class to ensure that
the plan can handle excluding checks.

Output examples:

{
    "nodes": {
        "details": {
            "puppet.example.com": {
                "Failed Test Count": 0,
                "Failed Test Details": [],
                "Passing Tests Count": 28
            }
        },
        "failing": [],
        "passing": [
            "puppet.example.com"
        ]
    },
    "errors": {
        "agent.example.com": "Missing the 'pe_status_check' fact"
    },
    "passed": false,
    "failing_node_count": 1,
    "passing_node_count": 1
}

{
  "nodes": {
      "details": {
          "puppet.example.com": {
              "Failed Test Count": 0,
              "Failed Test Details": [],
              "Passing Tests Count": 28
          }
      },
      "failing": [],
      "passing": [
          "puppet.example.com"
      ]
  },
  "errors": {},
  "passed": true,
  "failing_node_count": 0,
  "passing_node_count": 1
}