Command Line Arguments

[Zitchas]

It seems that I can never find information on the command line arguments for Endless Sky when I need them. So after spending a bunch of time digging through the source code for the specifics, some research online, and confirmation from Warp_core on the Swizzle6 discord, I put together the following wiki page to facilitate reference:

https://github.com/endless-sky/Endless-Sky-Delta/wiki/Command-Line-Arguments

[Zitchas]

I will probably PR it to the main wiki eventually, but I want to let it sit and perhaps improve it a bit first. This is basically a first draft.