Convert the test config map to a config list

[achilleas-k]

This PR converts the config-map.json file to a list.

The purpose of this change is to have more flexibility with configs that need to apply to multiple filter sets. For example, with the existing config map, it is not possible to apply the same config to the server-qcow2 file for Fedora and at the same time all image types for CentOS Stream 9, because the following is not possible:

{
    "configs/example.json": {
        "distros": [
            "fedora-*"
        ],
        "image-types": [
            "server-qcow2"
        ]
    },
    "configs/example.json": {
        "distros": [
            "centos-9"
        ]
    }
}

By converting the config map to a list, the above configuration is now possible as follows:

[
    {
        "path": "configs/example.json",
        "filters": {
            "distros": [
                "fedora-*"
            ],
            "image-types": [
                "server-qcow2"
            ]
        }
    },
    {
        "path": "configs/example.json",
        "filters": {
            "distros": [
                "centos-9"
            ]
        }
    }
]

[thozza]

This makes a lot of sense. Also, nice cleanup 😉

[achilleas-k]

This will probably conflict with some of the other open PRs and it's a pretty low priority right now. Not gonna set it to draft or anything, just people know.

[achilleas-k]

Rebased and fixed conflicts.

[croissanne]

LGTM but needs another round ;_; Let's prioritise this after the next rebase?