Build menu from a configuration object

[TheSlimvReal]

The top level menu is already very dynamic in its creation. For each button, a menu item is added in the app.module.ts. This process should be automated. The input will be an array of configuration objects and for each of these objects, a menu button will be added.
The configuration objects should at least consist of the name of the menu button, the icon which will be displayed next to the name and the component to which this button links.

Steps to do:

• Create a structure for the configuration object
• Create a function which gets an array of configuration objects and creates an menu button for each object
• Replace old procedure by this new one
• Write tests for these methods
• Optional: Also create routes and guards from the same configuration object (app.routing.ts)

relates to #222

[sleidig]

done with #510 / #504