Expose Lagoon tag/version in UI and API

[shreddedbacon]

Checklist

• Affected Issues have been mentioned in the Closing issues section
• Documentation has been written/updated
• PR title is ready for changelog and subsystem label(s) applied

Being able to know which version of Lagoon is currently running via the UI or API is handy when knowing which mutations/queries are supported, or quickly checking which version is running to know what feature set is available.

This PR adds the following query, which just exposes the LAGOON_VERSION environment variable.

query lagoonVersion {
  lagoonVersion
}

With the response:

{
  "data": {
    "lagoonVersion": "v1.4.0"
  }
}

And adds the footer to pages like so

Closing issues

closes #1384

[shreddedbacon]

The only thing with this PR is that it relies on LAGOON_VERSION being defined appropriately in the deployment for the api or ui services in openshift/kubernetes, rather than defaulting to what is in the image itself.

Case is if a hot-fix image rolls out for the api or ui services, this variable might have a different value in the image if it isn't configured in the deployment.