Import configuration files in sorted order

[MarcScheib]

Is your feature request related to a problem? Please describe.
In some cases, the configuration files are dependend on each other, e.g. a realm role that aggregates multiple others. In that case, it is important to have a specific order.

Describe the solution you'd like
Import the configuration files in the order given by the filename. This allows to prepend the files with numbers.