Use `Tar` to store trees of content?

[staticfloat]

For dense trees of content that are going to be bundled into a system image, it might make sense to use Tar.jl to do the bundling and extraction, as there's a good amount of corner cases around things like permissions that can get a little hairy across operating systems. Perhaps a good architecture to make it easier to deal with these things would be:

1. Use Tar.create() to generate a tarball (that can then be compressed in-memory, for space savings for larger bundles), store that tarball in the precompile cache.
2. Use Tar.extract() to write it out to disk on-demand just like it works now.

[MichaelHatherly]

Agreed, that would make sense.