Add certbot-auto uninstall docs (#8552)

This is part of #8545.

* add certbot-auto uninstall docs

* add uninstall.rst

* write a more aggressive sed command

certbot/docs/install.rst

@@ -243,6 +243,8 @@ Certbot-Auto
 
 We used to have a shell script named ``certbot-auto`` to help people install
 Certbot on UNIX operating systems, however, this script is no longer supported.
+If you want to uninstall ``certbot-auto``, you can follow our instructions
+:doc:`here <uninstall>`.
 
 Problems with Python virtual environment
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

certbot/docs/uninstall.rst

@@ -0,0 +1,16 @@
+=========================
+Uninstalling certbot-auto
+=========================
+
+To uninstall ``certbot-auto``, you need to do three things:
+
+1. If you added a cron job or systemd timer to automatically run
+   ``certbot-auto`` to renew your certificates, you should delete it. If you
+   did this by following our instructions, you can delete the entry added to
+   ``/etc/crontab`` by running a command like ``sudo sed -i '/certbot-auto/d'
+   /etc/crontab``.
+2. Delete the ``certbot-auto`` script. If you placed it in ``/usr/local/bin``
+   like we recommended, you can delete it by running ``sudo rm
+   /usr/local/bin/certbot-auto``.
+3. Delete the Certbot installation created by ``certbot-auto`` by running
+   ``sudo rm -rf /opt/eff.org``.