feat: Add Configuration.Builder load() method to load a file or resource

[rbygrave]

This then allows programmatic creation of Configuration which include the loading of files or resources like:

var fileSource = new File("./src/test/resources/yaml/minimal.yaml");

var configuration = Configuration.builder()
  .put("myExtraOne", "baz")
  .load(fileSource)          // load from a file
  .load("hi.properties")     // load from a resource
  .build();

With the file extension of .properties or .yaml/.yml used to determine which parser to use to parse and load the content for the file or resource.