text: Title: Allow to add title
  Body: It would be nice to be able to add a plot title on top of all the annotations. Something like:
  
  `statannotations.Annotator.Annotator.configure(title='foobar',...)`
  
  I guess the function would somehow have to take into account if annotations are to the left and the right (in this case the top is free and the title can be simpled added by using `ax.set_tile('foobar')`). If the annotations are on the top then the function would have to check where the upper end of the annotations lies and put the title there.