Enabling configuration injection points

By following the pattern established in Hyramata::Works, modules can
be mixed into the Hydramata::Configuration class exposing additional
configuration options.

The sequence of load for Rails, however, makes this complicated.

The initializers are loaded (i.e. `Hydramata.configure {|config| }`)
before the ActiveSupport.run_load_hooks are called. This means the
configuration must be captured and resolved after the load_hooks are
called.