Assembler function to be used as a Mix release step

This will assemble the necessary components to create a Bakeware executable that can be distributed across machines to run the script/application without extra environment setup (such as installing Elixir/Erlang, etc)

To use, add this to your release as a step after assembly:

def release do
  [
    demo: [
      steps: [:assemble, &Bakeware.assemble/1]
    ]
  ]
end

Bakeware adds the following options (these are at the same level as `:steps`
above):

* `:compression_level` - Zstandard compression level (1 to 19) where higher
  numbers generally result in better compression, but are slower to build