Rename/add labels for target group

[katrinleinweber]

@jkreklow had the idea of using good first issue to indicate an introductory event :-)

Since we don't need to funnel people from GitHub.com/TIBHannover through the N issue/s need/s help tag, shall we rename it to novices and add practitioners , experts or similar to indicate the target group?

I'm undecided about this. Mostly wanted to get the idea out of my head.