Create "versions" endpoint for tiles

[nvkelso]

Right now we advertise this in the tilejson only. We should have a more generic solution.

[nvkelso]

This should also advertise the recommended, generic attribution probably in txt and html form (see https://mapzen.com/rights/):

eg:

Provide Attribution
If you are using Mapzen services, you should use the following attribution statement:

© Mapzen, OpenStreetMap, and others

HTML snippet:

© <a href="https://www.mapzen.com/rights">Mapzen</a>, <a href="https://openstreetmap.org/copyright">OpenStreetMap</a> , and <a href="https://www.mapzen.com/rights/#services-and-data-sources">others</a>.

[nvkelso]

(Looks like both Pelias and Valhalla include attribution in their responses.)

[nvkelso]

And this might also impact / be useful to Tangram team? @matteblair

[matteblair]

How would a "versions" endpoint impact the vector tile API?

I like the idea of an API for recommended attribution. I'm not sure it's useful to include attribution information in every vector tile response since we show a dozen tiles on screen at once and we can only show one attribution string. If there were one place we could query for the attribution of tiles, we could do that once and display it while tiles are visible. Attribution display is still mostly an open question in tangram-es: tangrams/tangram-es#546

[nvkelso]

👍 I'd like to avoid attribution per tile, instead setting it for the whole service. If someone cares that much they can parse the features and their sources and mod it dynamically. But that's beyond basic scope.