docs: Instruct users to setup TLS using certbot

Part-of: <https://dev.funkwhale.audio/funkwhale/funkwhale/-/merge_requests/2319>

docs/administrator_documentation/installation_docs/debian.md

@@ -361,33 +361,19 @@ grep '${' /etc/nginx/sites-enabled/funkwhale.conf
 
 ## 10. Set up TLS
 
-To enable your users to connect to your pod securely, you need to set up {abbr}`TLS (Transport Layer Security)`. To do this, we recommend using the <acme.sh> script.
+To enable your users to connect to your pod securely, you need to set up {abbr}`TLS (Transport Layer Security)`. To do this, we recommend using certbot.
 
-1. Create the `/etc/certs` folder to store the certificates.
+1. Install certbot
 
    ```{code-block} sh
-   sudo mkdir /etc/certs
+   apt-get update
+   apt-get install certbot python3-certbot-nginx
    ```
 
-2. Download and run `acme.sh`. Replace `my@example.com` with your email address.
+2. Run certbot
 
    ```{code-block} sh
-   curl https://get.acme.sh | sudo sh -s email=my@example.com
+   sudo certbot --nginx -d $FUNKWHALE_HOSTNAME
    ```
 
-3. Generate a certificate. Replace `example.com` with your Funkwhale pod name. Use `/srv/funkwhale/front` as your web root folder.
-
-   ```{code-block} sh
-   sudo acme.sh --issue -d example.com -w /srv/funkwhale/front
-   ```
-
-4. Install the certificate to your Nginx config. Replace `example.com` with your Funkwhale pod name.
-
-   ```{code-block} sh
-   sudo acme.sh --install-cert -d example.com \
-      --key-file       /etc/certs/key.pem  \
-      --fullchain-file /etc/certs/cert.pem \
-      --reloadcmd     "service nginx force-reload"
-   ```
-
-That's it! acme.sh renews your certificate every 60 days, so you don't need to about renewing it.
+That's it! certbot renews your certificate every 60 days, so you don't need to worry about renewing it.