service: Convert autoyast partitioning section

[joseivanlopez]

The list of drives in the "partitioning" section of an AutoYaST profile is directly converted to json as "legacyAutoyastStorage" key.

See:

• feat(cli): agama profile autoyast command #1279
• Storage AutoYaST backward compatibility #1284

$ ./service/bin/agama-autoyast file:///path/to/profile.xml /tmp
$ cat /tmp/autoinst.json | jq

{
  "legacyAutoyastStorage": [
    {
      "device": "/dev/sda",
      "disklabel": "gpt",
      "enable_snapshots": true,
      "initialize": true,
      "partitions": [
        {
          "create": true,
          "partition_id": 263,
          "partition_nr": 1,
          "resize": false,
          "size": "8225280"
        }
      ],
      "type": "CT_DISK",
      "use": "all"
  ]
}

Note: Agama CLI complains when using file://:

$ agama profile autoyast file:///path/to/profile.xml
No such file or directory (os error 2)

[coveralls]

coverage: 70.273% (-0.008%) from 70.281%
when pulling 3442286 on joseivanlopez:autoyast-to-json
into e2c7a5a on openSUSE:master.

[coveralls]

coverage: 70.273% (-0.008%) from 70.281%
when pulling 3442286 on joseivanlopez:autoyast-to-json
into e2c7a5a on openSUSE:master.

[coveralls]

coverage: 70.273% (-0.008%) from 70.281%
when pulling bb64818 on joseivanlopez:autoyast-to-json
into e2c7a5a on openSUSE:master.