Make `create_library` work with Distributed

In order to use Distributed, the Julia session needs to start new Julia processes with some "special properties". Those Julia processes also need access to the Project.toml file so they can look up the UUID for packages that they are going to load in their session.

This is now fixed for `create_app` in https://github.com/JuliaLang/PackageCompiler.jl/pull/572 by bundling the Julia executable that comes with the Julia installation and also bundling the Project.toml that is used for the app. Something similar needs to be done for `create_library`.

Any thoughts @kmsquire?

Start by comparing the `create_app` implementation and pull request 572 with the `create_library` path. Trace how the Julia executable and Project.toml are bundled, then verify that Distributed-launched Julia processes can access the required project information and start with the needed special properties.

Written by the indexing model from the issue text.