Add new purchase order field to the tape table

As requested by operations (#Ops-964), we will add a new field to the TAPE table to quickly identify how the cartridge was purchased.

This field should be optional and only needs to be displayed when querying in JSON format.

Example:

[
  {
    "vid": "L86582",
    "mediaType": "LTO9",
    "vendor": "IBM-SONY",
>>>>"purchaseOrder": "DAI/8924306",
    "logicalLibrary": "SPC1L9",
    "tapepool": "r_cms_fam",
    "vo": "CMS",
    "encryptionKeyName": "-",
    "capacity": "18000000000000",
    "occupancy": "12027177761588",
    "lastFseq": "2968",
    "full": false,
    "fromCastor": false,
    "readMountCount": "0",
    "writeMountCount": "9"
  )
]