Support cloud providers other than AWS?

[mrgeorge]

Are there any plans to extend cogeo-tiler to enable deploying to other cloud providers like Azure or GCP? Looking over the code, it seems doable with modifications to serverless.yml and building geo-layer in the new environment. If there are no plans yet, I may take a swing at it for Azure.

Thanks for developing this repo! It's been a great resource to quickly stand up a performant tile service.