Rework fields/access to allow optional other access:* tags

[tordans]

The existing field https://github.com/openstreetmap/id-tagging-schema/blob/main/data/fields/access.json has a fixed list of access tags which is not ideal.
The access system in OSM is more complex that what the access field can handle right now.

One issue is, that we do not include tags that are present in the tag list but not hard coded in the keys array of the access field.

=> Possible solution: Add existing tags to the existing UI element at the end of the list

One issue is, that we include tags that are not relevant in many situations like horse=*. Some new mappers tend to add values just to fill out all options…

=> Possible solution: Move those tags to "more Tags" for this field so users can add them more easily but they are not as visible. That might need a special "show more access tags" UI element below the existing table.

One issue is, that presets cannot specify additional tags.

=> Possible solution: Our tooling only allows for copies of the fields/access which then can hold more or different keys. Ideally we would build this in a way that allows to "reference" all other properties and only duplicate the one "keys" property that we want to change. I assume that the schema-builder would need to be enhanced to allow referencing of more properties.

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Those changes might be first iterations for https://wiki.openstreetmap.org/wiki/Google_Summer_of_Code/2024/Project_ideas#Mapping_widget_for_real_world_access_restrictions