adding support for configurable session cookie parameters for express

It is often required for enterprise applications to set the session cookie parameters and not rely on express's defaults. These parameters are for example the cookie expiration time, and whether the session cookie will require the website to run in an SSL-enabled environment.

This PR adds support for default parameters on the cookie session and allows developers to set them as required globally, or per environment (dev, test, prod). Description on the session cookie parameters themselves have been added as well to make this easy to configure.