It may not mean doctor. RESIDENT used this way means something like, 'our person with a certain characteristic.'
So, whatever this organization is, they apparently have someone who is really good at something, i.e. a 'wonderboy'.
Example, imagine someone in your family is really good at taking pictures. You might tell people, 'my sister is our resident photographer.'
If someone at your job is very funny, you might say, 'he's our resident commedian.'