Because the previously shared workflows for IMDB-integration didn't work anymore I made my own. This is my first publicly shared workflow and this is also my first python-script. Probably things could have been programmed better, but it works for now.
So its not really fancy, but I think its workable, as long as IMDB doesn't change the API. Hope this workflow is some use for you all.
You can do it yourself right now. Preferences -> Features -> Contacts -- click on Phone and pick 'Pass to URL Scheme'. In the URL field, enter 'tel://{query}'. Now when you press enter on a contact phone number it'll open the call dialog. You _do_ have to press the Call button to initiate the call though.