Can I tweak/configure a deployment server to send out installation files to servers for installing forwarders?
No, the forwarder need to be installed some other way. After that, you can use the deployment server to deploy configuration files to the forwarders. I suggest you start by reading the forwarder documentation. It contains some good tips on how to install the forwarder remotely.
HTH
I guess though that you could upgrade an existing forwarder through the DS, if you send it out as an app, along with a scripted "input" that actually installs the new forwarder and then deletes itself...
Not that I've tried it, and I don't think I ever will 🙂