Ome ngff volume annotation

[leowe]

Steps to test:

• send a GET request to a route similar to GET http://localhost:9000/tracings/volume/zarr/18a17837-62e3-43b4-bcaf-da0baaec1b3d/.zattrs?token=secretSampleUserToken
• Get something back like

{
    "multiscales": [
        {
            "version": "0.4",
            "name": "18a17837-62e3-43b4-bcaf-da0baaec1b3d",
            "axes": [
                {
                    "name": "c",
                    "type": "channel"
                },
                {
                    "name": "x",
                    "type": "space",
                    "unit": "nanometer"
                },
                {
                    "name": "y",
                    "type": "space",
                    "unit": "nanometer"
                },
                {
                    "name": "z",
                    "type": "space",
                    "unit": "nanometer"
                }
            ],
            "datasets": [
                {
                    "path": "1",
                    "coordinateTranformations": [
                        {
                            "type": "scale",
                            "scale": [
                                1,
                                11.239999771118164,
                                11.239999771118164,
                                28
                            ]
                        }
                    ]
                },
                {
                    "path": "2-2-1",
                    "coordinateTranformations": [
                        {
                            "type": "scale",
                            "scale": [
                                1,
                                22.479999542236328,
                                22.479999542236328,
                                28
                            ]
                        }
                    ]
                }
            ]
        }
    ]
}

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• Updated (unreleased) changelog
• Ready for review