Build refactor

[filmor]

Refactor build logic to remove TOML dependency, implements #685.

[scrogson]

@filmor are there other benefits to this? Otherwise, it seems a bit heavy handed if we're just trying to remove a dependency.

[filmor]

• It doesn't guess the artifact anymore but instead gets it from Rust's stable interface
• It implements Rename libs as we copy them out of target #685, which ensures that the shared library is named the same on all platforms so the .beam file becomes platform-independent