EX-8130 lipe: Add JSON report type for dirs stats

EX-8130 lipe: Add JSON report type for dirs stats

This patch adds functions for displaying size statistics
for directories in the general report. This is necessary
to merge reports in the future.
This patch adds support for *.json format only.

Example structure:
"DirectoriesStats":{
  "SourceDirectory":"",
  "MaxDepth":4,
  "TotalSizeBytes":104861696,
  "TotalAllocatedSizeBytes":104861696,
  "RatingMinSizeBytes":0,
  "RatingMaxSizeBytes":104861696,
  "Rating":[
    {
      "RatingPosition":0,
      "SizeBytes":104861696,
      "AllocatedSizeBytes":104861696,
      "Depth":0,
      "FilesCount":1,
      "DirsCount":1,
      "UserID":0,
      "FID":"0x200000401:0x2:0x0",
      "DirectoryName":"d308.sanity-lipe-scan3",
      "Path":"d308.sanity-lipe-scan3"
    }
  ],
  "MainTree":{
    "ChildDirectories":[
      {
        "SizeBytes":104861696,
        "AllocatedSizeBytes":104861696,
        "Depth":0,
        "FilesCount":1,
        "DirsCount":1,
        "UserID":0,
        "GroupID":0,
        "ProjID":0,
        "Atime":1713188451,
        "Mtime":1713188451,
        "Ctime":1713188451,
        "Crtime":1713188451,
        "FID":"0x200000401:0x2:0x0",
        "DirectoryName":"d308.sanity-lipe-scan3",
        "Path":"d308.sanity-lipe-scan3",
        "ChildDirectories":[
        ]
      }
    ]
  }
}

Additional fields will also be added, and some
checks to display file statistics in JSON format.

Test-Parameters: trivial testlist=sanity-lipe-scan3
Signed-off-by: Vitaliy Kuznetsov <vkuznetsov@ddn.com>
Change-Id: Ib250dc684cdd16e21187a710b855f4fffcf0eed1
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/54283
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>