title: Django CharField with no max length
body: <p>I have a frontend that will be sending bas64 images, I will put those very large strings on a variable and send it to a form. What kind of <code>FormField</code> can I use? </p>
  
  <p>The regular <code>CharFields</code> need a <code>max_length</code>. Since it is a very large string, I don't know the length it could have.</p>