Customizable folder names

[werli]

Making folder names custom would be a huge enhancement for me, as the format option provides good, but obviously not perfect customisation.

This could be implemented by renaming during or after initial course synchronisation.

During synchronisation the option [r] could be used. Renaming after synchronisation could be kinda hard, so renaming during would probably do the trick.

[werli]

maybe label as Enhancement

[fknorr]

This will be partially implemented by allowing to change course names, types and abbreviations. See the course-cmd branch for a preview.