json-directory: Load JSON from files in a directory structure

Provides utilities for reading JSON structures out of directories. Directory entries become keys in a map, and the values are sourced from the contets of each entry.

• Directories are recured into
• Files ending with .json are read as JSON values
• Everything else is interpreted as a string

The example directory in this repository would result in the following JSON value.

{
  "empty": {},
  "a": "This is files will have its contents written into a JSON string.\n",
  "d": {
    "example": "Sometimes it's convenient to embed some raw JSON"
  },
  "b": 42,
  "c": {
    "nested": "You can nest directories to create a tree structure.\n"
  }
}