Preset field inheritance

[quincylvania]

There is a lot of duplicated field data in the presets. For instance, most of the shop presets have the same fields:

    "fields": [
        "name",
        "operator",
        "address",
        "building_area",
        "opening_hours",
        "payment_multi"
    ]

If we want to change this default list, we need to do it dozens of times to be consistent. This issue is compounded by the new moreFields property.

The presets should inherit their fields and moreFields properties from the "parent" preset if they are not manually defined. For instance, shop/convenience should automatically take the fields of shop if the user doesn't provide more explicit values.

A special field value such as {inherit} could allow for adding onto the inherited fields, like so:

{
    "icon": "maki-clothing-store",
    "fields": [
        "{inherit}",
        "clothes"
    ],
    "geometry": [
        "point",
        "area"
    ],
    "tags": {
        "shop": "clothes"
    },
    "name": "Clothing Store"
}

An alternative solution would be to allow targeting a specific preset, but I think "parent" inheritance fits most cases.