doc: update README.md

- Fix a broken link (fixes #6780)
- Set direct links
- Add a link to the Docker installation guide

README.md

 
 On the client side, no installation is necessary. You just point your browser to the URL of your deployment. This section is about installing a Jitsi Meet suite on your server and hosting your own conferencing service.
 
-Installing Jitsi Meet is a simple experience. For Debian-based system, following the [quick-install](https://github.com/jitsi/jitsi-meet/blob/master/doc/quick-install.md) document, which uses the package system. You can also see a demonstration of the process in [this tutorial video](https://jitsi.org/tutorial).
+Installing Jitsi Meet is a simple experience. For Debian-based system, following the [quick install](https://jitsi.github.io/handbook/docs/devops-guide/devops-guide-quickstart) document, which uses the package system. You can also see a demonstration of the process in [this tutorial video](https://jitsi.org/tutorial).
 
-For other systems, or if you wish to install all components manually, see the [detailed manual installation instructions](https://github.com/jitsi/jitsi-meet/blob/master/doc/manual-install.md).
+For other systems, or if you wish to install all components manually, see the [detailed manual installation instructions](https://jitsi.github.io/handbook/docs/devops-guide/devops-guide-manual).
+
+Installation with Docker is also available. Please see the [instruction](https://jitsi.github.io/handbook/docs/devops-guide/devops-guide-docker).
 
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