Test program changes

Added a setup script for the test program, since the previous Makefile could potentially clobber user files.

Pull latest module in sample program

Sample program generates go.mod and go.sum on the fly so we pull the very latest version of vite-go.

Added sample program

Added sample program to show how to integrate the module into code and get the web server to serve the contents of dist/assets.

Reduce public interface

Remove the manifest parser from the public interface.

Doc changes

Added config information

First draft of README

Created a somewhat useful README. Needs a test drive.