Database Connection Flags

At DigitalOcean Database panel, you can get the `mysql -u...` command snipped, which is called `Flags` on the `Connection Details` section.

With `doctl` i wasn't able to find a way to print that for me, i know i can use `--output=json | jq` and build myself but would be very useful to have this ready for me, even better if we do not include `-D defaultdb` part.

```bash
doctl db connection [dbid] --format=Flags
```