Tracking server redirection - stop a jump from dev to prod services

[mgcam]

Most likely the code of the staging_urls() method in the npg::view class has to be refactored to stop using so many values from the configuration file.

The dependency on the npg_tracking configuration file should be reviewed. If a few simple config options are required, they can be added to the application's own data/config.ini file.

We might consider propagation of the current port to the URL used for redirection.