Send apollo version back to lightning

[josephjclark]

All apollo APIs should include a version number in the response. This helps us analyse metrics by seeing which version generated a certain payload.

We could do this in a few ways:

• as a response header on all responses. Totally generic. Metrics tools would have to look for it and use it
• as a top-level property in all payloads. I don't love mandating this, and it might be too direct. But makes it easier to reason about
• as a property on the meta key. The most obvious approach. Might be a bit hard to use in metrics though - perhaps we can pull it out of the response payload