Hosting - custom caching in s3/cloudfront

It would be nice if there was a way to define custom s3 metadata for deployed projects.

Setting cache-control metadata in s3 gets passed through to cloud front and then on to the user. But it doesn't seem like there is an easy way to set the cache-control metadata during a deployment.

Maybe there could be a s3Headers.json file with something like:

`[
{files:"**/*.jpg", metaData:[{"Cache-Control":"max-age:100"}]},
{files:"**/*.js", metaData:[{"Cache-Control":"max-age:10", "other-header":"data"}]}
]`

The issue proposes an s3Headers.json file containing file patterns and S3 metadata such as Cache-Control. Start by tracing the CLI's hosting deployment path for S3 and CloudFront; done means matching deployed files receive the configured metadata during deployment.

Written by the indexing model from the issue text.