Archive old registry

[bcpeinhardt]

From @Kira-Pilot :

I was thinking we should probably update the README for and then archive the old Registry. We could update the project name as well and then retitle the new registry.

[bcpeinhardt]

I have a PR up updating the readme for the old registry, as soon as it's merged I'll archive it. The new registry has been retitled "coder-registry".