Disable new zip download / registration pathway

In order to facilitate getting current code out, disable the new download / install and auto-registration pathway.

Testing:
1. Set up a test central server, and make sure "install" goes to the wiki, with github instructions
2. Set up a new repo in git, and run `setup`.  Make sure the device does not register during setup.
3. On the new device, see that the old messages for registering appear, and that you can manually register with the test central server (as done previously).

I've tested all of these myself, but another set of hands to test would be appreciated!