Use deb822-style APT repository configuration

[merlinz01]

Fixes #559

- What I did

Refactor Docker repository setup to support new deb822 format and provide warnings for existing configurations.

- How I did it

Typing on a keyboard, I guess.

- How to verify it

Install on recent Debian or Ubuntu. /etc/apt/sources.list.d/debian.sources should contain something like this:

Types: deb
URIs: https://download.docker.com/linux/debian
Suites: trixie
Components: stable
Architectures: amd64
Signed-By: /etc/apt/keyrings/docker.asc

- Description for the changelog

Use deb822-style APT repository configuration on Debian/Ubuntu versions that support it.

- A picture of a cute animal (not mandatory but encouraged)

[thaJeztah]

thanks! left some quick comments after glancing over.

[thaJeztah]

I think we already make these old distros a hard failure, so we can probably skip this check; older distros are no longer supported by the script, so it's fine if things would fail.

[merlinz01]

I don't see any hard failure here. Is that in some other component?

        # Print deprecation warnings for distro versions that recently reached EOL,
        # but may still be commonly used (especially LTS versions).
        case "$lsb_dist.$dist_version" in
                centos.8|centos.7|rhel.7)
                        deprecation_notice "$lsb_dist" "$dist_version"
                        ;;
                debian.buster|debian.stretch|debian.jessie)
                        deprecation_notice "$lsb_dist" "$dist_version"
                        ;;
                raspbian.buster|raspbian.stretch|raspbian.jessie)
                        deprecation_notice "$lsb_dist" "$dist_version"
                        ;;
                ubuntu.focal|ubuntu.bionic|ubuntu.xenial|ubuntu.trusty)
                        deprecation_notice "$lsb_dist" "$dist_version"
                        ;;
                ubuntu.oracular|ubuntu.mantic|ubuntu.lunar|ubuntu.kinetic|ubuntu.impish|ubuntu.hirsute|ubuntu.groovy|ubuntu.eoan|ubuntu.disco|ubuntu.cosmic)
                        deprecation_notice "$lsb_dist" "$dist_version"
                        ;;
                fedora.*)
                        if [ "$dist_version" -lt 41 ]; then
                                deprecation_notice "$lsb_dist" "$dist_version"
                        fi
                        ;;
        esac

[thaJeztah]

Oh, you're right; it's not a hard failure (we may have in the past), but it sleeps for 10 seconds and a warning;

docker-install/install.sh

Line 273 in 2687d91

deprecation_notice() {

Regardless, we should prefer keeping the script focused on what's still supported, and try to avoid complexity for things no longer supported; users can still download older versions of the script, or (better) create their own implementation targeted at their situation.

[merlinz01]

So should I change it to a hard fail for those distro versions?

[thaJeztah]

We already have a warning if the script detects that docker is installed already (as its main purpose is for fresh installs, not upgrades); honestly, I think we can keep it simple; assume the docker.list is created either by this script, or manually, but for the docker installation, so just remove it;

if [ -f /etc/apt/sources.list.d/docker.list ]; then
	rm -f /etc/apt/sources.list.d/docker.list
fi

[merlinz01]

Done.