Added

• Added inline docs + typespec public functions
• Added tests for PolyPost.Builder and PolyPost.Depot modules
• Added support for code highlighting using makeup in code blocks
• Added storage of content into ETS tables accessible via the PolyPost.Depot processes
• Added support to load files directly from configured, splattable paths
• Added PolyPost.Resource behaviour to specify build/3 function callbacks for managing parsed markdown + metadata
• Added README with documentation for basic installing and usage of this library
• Added license (Apache 2.0) to project