title: Row titles for matplotlib subplot
body: <p>In matplotlib, Is it possible to set a a separate title for each row of subplots in addition to the title set for the entire figure and the title set for each individual plot? This would correspond to the orange text in the figure below.
  <img src="https://i.stack.imgur.com/K7950.png" alt="enter image description here"></p>
  
  <p>If not, how would you get around this problem? Create a separate column of empty subplots to the left and fill them with the orange text?</p>
  
  <p>I am aware that it is possible to manually position each single title using <code>text()</code> or <code>annotate()</code>, but that usually requires a lot of tweaking and I have many subplots. Is there a smoother solution?</p>