Feature: New option to push message every x lines(default 1)

I'm watching logs for some filesystems and want notified when there are new entries. I'm using:

```sh
`journalctl -kf | xargs -L 1 gotify p
```

That is working great! I'd like to make it integrated so as to not worry as much about buffering and to not need the `xargs` and be more portable for others.

Something like:
```sh
journalctl -kf | gotify p -L 1
```

And the option could be:
```
gotify push
--lines value, -L value Push a message every 'value' lines (default: 1)
```

Would this be a good idea?