Have a CDN with all API responses statically generated

[wilzbach]

Similar to the new Netlify preview, we could have a DUB mirror that updates itself daily (Travis cron) and is at the end of the chain and the last resort.

The idea: prefetch all responses with wget/curl and deploy them to a CDN (GitHub Pages, Netlify, ...).
Netlify can handle a few GBs quite fine (the docarchives.dlang.io currently take 3G), but I doubt that it
will be that much. Currently the uncompressed JSON of all packages is 38M
Netlify does support redirects, so the zips don't need to be downloaded.

Downsides/problems:

• search won't work (ok, because this is last resort, s.t. building always works)

[bausshf]

You could possibly make search work by generating a static javascript object, then search through that with javascript, instead of using an api call.

Of course that would be additional functionality to add on top.

[MartinNowak]

I'd rather argue for migrating the registry to properly hosted servers and a simple HA setup instead of complicating the architecture with such a strong requirement (or uglifying it with a hack).
We could possibly funnel through cloudfront instead of using curl/wget, but I have bad experience with long 503s with unreliable backend servers.

In fact I'm preparing migration to a couple of VPS instances atm., let's try the proved approach first.