File Layout

Container for laying out files in a single container for writing to disk. Notes:

1. Polymorphic over the representation of the file contents. For rendering, writeFiles requires the file content representation satisfy Renderable.
2. Only permits writing files/directories relative to a base path provided. Does not permit `..`, ., nor ~ as directory names.
3. System-local path separator is forbidden from use in directory names.
4. Assumes host file system is case-sensitive (i.e., recognizes txt and `a.txt` as different paths).

Create a file FileLayout.

Create a directory FileLayout, optionally containing any number of nested files.

Write a FileLayout to disk about a base path.

Disclaimer: Fails if files/directories already exist. This is problematic for case-insensitive file systems where different paths reference the same.