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

[chanseokoh]

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 to use Jib. Optionally being able to specify a checksum as 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 assimilate functionalities other plugins or facilities that already provide them well (e.g., downloading/copying/unpacking resources into extraDirectories).

[tandeday]

I think this is outside the scope of this plugin. Instead let this happen elsewhere in the maven build, requiring the programmer to specify extracting the contents under target/ and then let jib include that instead.

[raizoor]

I think it will be usefull. This weekend e need simular issue than you @chanseokoh .. But I don't know how many job time and changes will be necessary.

[fragaLY]

It really would be a nice feature.