Update Start up guide

[SpaceTowel]

1. Update step 1, no longer need batteries
2. Step 2, is the connector listed correct? do we need to update photo?

[ISS-Mimic]

Correct, no more batteries. And step 2 is not correct either, just need to plug in the USB hub

[cactus314]

Step 3 will change as well. So long as there is an internet connection, the RPi clock should set itself, and I think I have the desktop icon working to launch the Mimic code without requiring going through a terminal window - though we should include instructions for both methods just in case.

[streadgold]

@cactus314 so I'm not sure if there's something about the boeing external network preventing this, but when testing at work I have always had to set the time manually. I'd say leave that in there to double check just in case