RealmURL / Asset Server, better NGinX config for web client

[noahgibbs]

Right now we're using the DGD server to serve Orchil. That's sub-optimal - it does DGD authentication for every HTML, CSS and JS file, for instance. We also have essentially no asset server set up, so things like map images are broken.

We need to:

• Serve Orchil's static files via NGinX (this is just an NGinX config change)
• Have an asset repository somewhere in a known location [for local config] [and for stackscript config]
• Set up the realmURL properly so that it links into the asset repository

Once that's done, assets and realmURL should work the same way for ChatTheatre cold-boot SkotOS as for other SkotOS games.

Est: 1.5-2 days.

[ChristopherA]

@saraht45 should be testing @noahgibbs changes here once he finishes these, and she should sure that there is documentation for what tools currently use files in NGinX (for instance map fragments, css for start story, etc.), where these files are installed the NGinX tree, and document other uses of realmURL (maybe search the code).