Add option to disable Draco compression

[OmarShehata]

Now that ion has a REST API and more engines are picking up 3D Tiles, we might want to consider adding an option to turn off Draco compression when tiling, in the case where the client doesn't support it. Currently all 3D Tiles produced on ion are Draco compressed by default.

I imagine this would be easy to add since the tiling pipeline itself supports this option, it's just not exposed on the ion platform (for example, see --disable-geometry-compression in the CLI docs https://cesium.com/docs/on-premise/tilers/3d-buildings/).

If this is something that you'd be interested in seeing, please 👍 this issue, and/or comment below and let us know what client/engine you're using.

[OmarShehata]

Just got another request for this to get 3D Tiles (b3dm) streaming in Unity. I'm not sure if we should expose it on all the tilers or just for 3D models right now.

I also imagine we'd want to expose this on the REST API too.

[OmarShehata]

This is now possible to toggle on ion! See the change log here: https://cesium.com/ion/changelog#2019-08-07