Able to specify archive URL (tar, zip, tar.gz, ...) for extraDirectories

This has been brought up a few times, and recently, I wished I could specify an archive URL for `extraDirectories` when I tried migrating [microservices-demo](https://github.com/chanseokoh/microservices-demo/blob/67ed7d65f76237eefb565baf51966b30640950f3/src/adservice/build.gradle#L85-L108) to use Jib. Optionally being able to specify a checksum as [gradle-download-task](https://github.com/michel-kraemer/gradle-download-task) does.

However, probably `extraDirectories` will need #1581 to be able to specify an unpack destination for this to be useful. Also, I realized often you want some filtering to be able to selectively copy only what you want.

That brings us back into our previous debates where Jib wants to implement functionalities (i.e., re-invent the wheel) that are already well supported by Gradle or other popular plugins (e.g., downloading/copying/unpacking resources into `extraDirectories`).