Allow to add classes for external and mail links

Let's start with this one! Definitely doable in a timely manner.

After a whole lot of work this is finally up and running! To review it is!

This time we might be done!

Just some final alignments.

Please also add tests like the module already has.

With all of it working out fine now, I hope that was the last from me! :)

Well done! Nice and helpful feature!

Merged! :)

Automatically closed - issue fixed for 2 weeks with no activity.