title: django-cms remove plugin via API
body: <p>In my website I am making use of the django-cms (by then 2.4.3, now using 3.0.13) API to create pages in the backgroud when, for example, a new department is created.</p>
  
  <pre><code>        from cms.api import create_page, add_plugin
  
          instance.page = create_page(
              title=instance.name,
              language='en',
              published=True,
              template='template.html',
          )
          placeholder_header = instance.page.placeholders.get(slot='header_img')
          add_plugin(
              placeholder=placeholder_header,
              plugin_type='SomeRandomPlugin',
              language='en',
              department=instance,
          )
          publish_page(page=instance.page, user=User.objects.filter(is_superuser__exact=True).latest('pk'))
          # [...]
  </code></pre>
  
  <p>This works correctly when I want to create the page. But when I want to modify it, I first need to delete the existing plugin to create it again with the new values. But the official API does not seem to allow this. Is there a way to remove or modify an existing plugin?</p>
  
  <p>Thank you in advance for all your feedback.</p>