After upgrading to Mojave, applications like Skype or Skype for Business stopped receiving audio and camera input. On Mojave, applications are supposed to be triggering an alert asking for permissions to access those resources, but after upgrading to Mojave, these applications never did that.
Long story short: I removed
rm -rf ~/Library/Application\ Support/com.apple.TCC
logged out and back in. Now it works. In that directory, those permissions are stored.
As written here, within said directory, there in fact is a TCC.db which is an SQLite database and can be edited.