Feature/#114 issue templates
This MR provides issue templates (bug, feature request) for GitLab to improve our development workflow.
We can use this for every bug and feature request issue.
Are there parts of the documentation we have to adjust?
Yes, and I already did! (in CONTRIBUTING.md)
Are we able to test this new feature?
I'm not sure if this makes sense since it's not an enhancement to the software itself.
Closes #114 (closed).