[phpcgijs] [imporvement] Adding dynamic PHP-CGI path configuration to the repo that can be instantiated from express server.

[phpcgijs] [improvement] [docs]
Adding dynamic PHP-CGI path configuration to the repo that can be instantiated from express server.

[Commit]: Adding dynamic PHP-CGI path configuration to the repo that can be instantiated from express server. Available Tests pass through. Adding docs for relevant changes.