Report filtered subscription data to Export Service in JSON

The expectation for this story is that when a subscription export request is encountered, we'll actually query the database for data, and then POST it back to the export service.

Requirements:

• Implement the fetchData method for subscriptions export in swatch-subscription-sync
• fetched data should always be limited to the orgId that the user is allowed to access.  There's a redhatorgid field on the message, as well as the an org id in the base64 encoded data.x-rh-identity field.
• consult the data.filters field when querying the database for subscription data. The following filter parameters must be supported:
  • product_id
  • sla
  • usage
  • uom metric_id
  • billing_provider
  • billing_account_id
  • display_name_contains
  • category
• If any extra filters are provided, log it and move on.
• If no filters are provided, return unfiltered results (with the exception of limiting by appropriate org id)
• fetchData must throw an exception for bad product_id, sla, usage, uom, billing_provider, or category
  • The listener must catch and report these errors with exportClient.downloadExportError with error code 400 and a message explaining what parameter(s) are bad. The error message may be limited to a single parameter.
• If the data.format != json, continue to throw not yet implemented exception.
• If no exceptions are thrown, implement uploadJson and call exportClient.downloadExportUpload with JSON-formatted data
  • Create a yaml json schema file in src/main/resources/subscriptions-export.yaml and generate the POJO model using jsonSchema2Pojo.

JSON example:

 {
    "subscriptions": [
        {
            "sku": "RH00001",
            "product_name": "Red Hat Enterprise Linux for Virtual Datacenters, Premium",
            "service_level": "Premium",
            "usage": "Production",
            "metric_id": "Sockets",
            "subscriptions": [
                {
                    "id": "123456",
                    "number": "123456",
                    "quantity": 42,
                    "capacity": 0,
                    "hypervisor_capacity": 42,
                    "begin": "2021-11-28T16:38:12.951046Z",
                    "end": "2023-11-28T16:38:12.951046Z",
                }
            ]
        }
    ]
}

• Use streams wherever possible to mitigate OOM issues

Testing:

• Attempted export with bad parameter(s) should fail with a message explaining which parameter(s) are bad.
• Attempted export for JSON should succeed (after correcting bad parameters)
• Attempted export for CSV should fail because the format is not yet implemented.