[Feature Request] Allow passing an Asset

[benface]

It would be nice if the rev() function accepted Asset elements in addition to file paths. I suppose remote volumes (S3, Google Cloud, etc.) would be more work since it would have to download the file (and I'm not sure it's a good idea performance-wise), but local volumes would work like any other asset.

[benface]

I also posted this feature request to Craft CMS itself: craftcms/cms#5824

If it ends up being accepted, then there would be no need to do it in this plugin.