Docker Registry is now available

[girish]

Hi all,
Docker Registry is now available in the app store. Thanks to @mario for getting this going and @mehdi for some creative ideas on how to support this!

Code: https://git.cloudron.io/cloudron/docker-registry-app.git
Docs: https://docs.cloudron.io/apps/docker-registry/
App store: https://www.cloudron.io/store/com.docker.registry.html

IMPORTANT: this app only works with Cloudron 6.1. If you want to try immediately, you can go to Settings -> Check For Updates and update to 6.1.1. Unfortunately, there are a few small regression in 6.1.1 (for example, the app disk usage graphs are not working, sogo login is broken). So please update only if you can live with these issues. 6.1.2 should be on monday or so.