docs: update the list of Docker images with Spack preinstalled (#31003)

Also, update the image in the docs and use ghcr.io

lib/spack/docs/containers.rst

@@ -109,9 +109,10 @@ Spack Images on Docker Hub
 --------------------------
 
 Docker images with Spack preinstalled and ready to be used are
-built on `Docker Hub <https://hub.docker.com/u/spack>`_
-at every push to ``develop`` or to a release branch. The OS that
-are currently supported are summarized in the table below:
+built when a release is tagged, or nightly on ``develop``. The images
+are then pushed both to `Docker Hub <https://hub.docker.com/u/spack>`_
+and to `GitHub Container Registry <https://github.com/orgs/spack/packages?repo_name=spack>`_.
+The OS that are currently supported are summarized in the table below:
 
 .. _containers-supported-os:
 
@@ -121,22 +122,31 @@ are currently supported are summarized in the table below:
    * - Operating System
      - Base Image
      - Spack Image
-   * - Ubuntu 16.04
-     - ``ubuntu:16.04``
-     - ``spack/ubuntu-xenial``
    * - Ubuntu 18.04
      - ``ubuntu:18.04``
      - ``spack/ubuntu-bionic``
+   * - Ubuntu 20.04
+     - ``ubuntu:20.04``
+     - ``spack/ubuntu-focal``
+   * - Ubuntu 22.04
+     - ``ubuntu:22.04``
+     - ``spack/ubuntu-jammy``
    * - CentOS 7
      - ``centos:7``
      - ``spack/centos7``
+   * - CentOS Stream
+     - ``quay.io/centos/centos:stream``
+     - ``spack/centos-stream``
    * - openSUSE Leap
      - ``opensuse/leap``
      - ``spack/leap15``
+   * - Amazon Linux 2
+     - ``amazonlinux:2``
+     - ``spack/amazon-linux``
 
 All the images are tagged with the corresponding release of Spack:
 
-.. image:: dockerhub_spack.png
+.. image:: images/ghcr_spack.png
 
 with the exception of the ``latest`` tag that points to the HEAD
 of the ``develop`` branch. These images are available for anyone