Switch DNS over pkgn-->pkgs

[tonyg]

cc @samth

This also entails fiddling with the config on pkgd to fix up the URLs so they don't have the /pkgn/ in them.

[jeapostrophe]

• [x] Confirm rename -- pkgs.racket-lang.org becomes pkgo.racket-lang.org -- pkgn.racket-lang.org becomes pkgs.racket-lang.org
• [x] What config files need to change? -- racket-pkg-website/configs/live.rkt fields aws-s3-bucket+path, static-urlprefix, dynamic-static-urlprefix -- pkg-index/official/common.rkt fields s3-bucket -- pkg-index/official/configs/live.rkt fields atom-package-url-format-string, s3-bucket
• [x] Stop the server
• [x] Update the config files
• [x] Rename the buckets
• [x] Redirect pkgn.racket-lang.org to pkgs.racket-lang.org on CloudFlare
• [x] Start the server
• [x] Redirect pkgn to pkgs?

[jeapostrophe]

@tonyg please confirm this plan

[jeapostrophe]

@tonyg I'm going to execute this plan in about a week, so please confirm it if you can.

[tonyg]

I've not yet reviewed the plan in detail (but in broad outline it looks good!), but wanted to ask whether we need to resolve #40 properly before we switch over, since that might affect the actual operation of the catalog, rather than just the UI.

[jeapostrophe]

Almost everything is working. There are a few problems:

• [x] http://pkgn.racket-lang.org is failing because of a bucket/CNAME mismatch. I have an idea for how to fix this
• [x] changes to files are not yet committed