Make configuration directory passable to scriptlet runners

This pull request changes the arguments passed to the scriptlet entry points `xp.scriptlet.Runner` and `xp.scriptlet.Inspect` to include the configuration directory. The argument order is now:

1. The web root - defaults to $CWD
2. :new:  **The configuration directory - defaults to $WEB_ROOT/etc**
3. The server profile - defaults to "dev"
4. The server address - defaults to "localhost:8080"

The `xpws` runner will be adapted to support a "-c" command line option to change this directory