For systemd users, you'd need a command like:
```
logagent-setup -i TOKEN_GOES_HERE -j
```
The `-j` part signals that we don't want to tail `/var/log`, but rather accept input from `systemd-journal-upload`. Without `-j`, there should be no difference.

With `-j`, we do the following:
- install `systemd-journal-upload` if it doesn't exist (via `apt-get` or `yum`)
- set up `logagent.conf` to listen to `localhost:5731` (a random port) and parse journal data
- set up `journal-upload.conf` to send data to `localhost:5731` using the provided token
- restart both journald-upload and logagent

Co-authored-by: Ciprian Hacman <ciprian.hacman@sematext.com>