Fix to address data

[nickevansuk]

Applying rules:

• null properties or objects that contain only null values should not be included (null properties or objects that contain only null values should not be included openactive-archive/developer-microsite#9)
• Missing details in the PostalAddress may result in the event not being listed in Google Reserve (Missing details in the PostalAddress may result in the event not being listed in Google Reserve openactive-archive/developer-microsite#19)

For this example:

• Position in feed: http://lr-api.staging.phoenixdigital.agency/public/v1/rides?from=2018-01-01+01%3A02%3A10
• Ride: https://www.letsride.co.uk/rides/hearts-delight-loop-12-14mph-no-drop

Note the postcode is included in the ride website, but is not present in the feed.

Not like this:

{
  "@context": "https://www.openactive.io/ns/oa.jsonld",
  "type": "Event",
  "location": {
    "type": "Place",
    "description": null,
    "address": {
      "type": "PostalAddress",
      "addressCountry": "GB",
      "addressLocality": null,
      "addressRegion": "unknown",
      "postalCode": null,
      "streetAddress": " "
    }
  }
}

Like this:

{
  "@context": "https://www.openactive.io/ns/oa.jsonld",
  "type": "Event",
  "location": {
    "type": "Place",
    "address": {
      "type": "PostalAddress",
      "addressCountry": "GB",
      "postalCode": "IP1 4HT"
    }
  }
}