New Export/Import pointHierarchy. [ScadaLTS]

Issue:
#526

The task involved:

Adding and configuring vuejs to incremental rewriting of user interface.
Adding REST API for export import.
Adding component vuejs in order to realize Export/Import (with progress bar and cancel button).
Programming the next stages of import.

How exports work

Export collects data witch create
array of folders with xid points in the following format.

  "folders": [
    {
      "parentXid": null,
      "name": "Test",
      "xidFolder": "DIR_1",
      "pointXids": [
        "DP_1",
        "DP_2"
      ]
    },
    {
      "parentXid": "DIR_1",
      "name": "Test",
      "xidFolder": "DIR_2",
      "pointXids": [
        "DP_3",
        "DP_4"
      ]
    }
   ...
  ]
}

How import works

Required fields: parentXid, name, xidFolder, pointXids.

Optional fields: toDelete: (true/false)

Examples of use:

Adding folder and moving it to the xid DIR_1 folder and moving DP_3, DP-4 points to xid DIR__NOT_EXIST folder witch will be created.

  "folders": [
        {
            "parentXid": "DIR_1",
             "name": "Test",
             "xidFolder": "DIR__NOT_EXIST", 
             "pointXids": [
                "DP_3",
                "DP_4"
              ]
        }
         ]
}

Deleting a folder:

  "folders": [
    {
        "parentXid": null,
         "name": "Test",
         "xidFolder": "DIR_1",
         "pointXids": [
          ],
        "toDelete":"true"
    }
    ]
    }

Renaming the folder

  "folders": [
{
    "parentXid": null,
     "name": "Test_NEW_NAME",
     "xidFolder": "DIR_2",
     "pointXids": [
          ],
    "toDelete":"false"
}
]
}

Moving points to pointXids: ["DP_1", "DP_2", "DP_3", "DP_4"] to folder o xidFolder: "DIR_2"

  "folders": [
{
    "parentXid": null,
     "name": "Test",
     "xidFolder": "DIR_2",
     "pointXids": [
        "DP_1",
         "DP_2", 
        "DP_3",
         "DP_4"
          ],
    "toDelete":"false"
}
]
}