Remove building field from presets for horse_riding facility and for riding arena

[Hufkratzer]

I propose to remove the building field from the presets a) for horse_riding facility and b) for riding arena

Reasons:

a) horse_riding facility

The tag leisure=horse_riding is intended for the whole area which can contain many different things like riding arenas, riding halls / indoor arenas, other buildings, paddocks etc, but not for a specific building. Horses usually live outdoors (at least during the day), therefore such horse riding facilities usually contain outdoor space. The building field in this preset temps mappers to use the tag wrongly.

• https://github.com/openstreetmap/id-tagging-schema/blob/main/data/presets/leisure/horse_riding.json
• https://wiki.openstreetmap.org/wiki/Tag:leisure=horse_riding
• https://wiki.openstreetmap.org/wiki/Riding

b) riding arena

Since August of this year (2021) it is discouraged in the wiki to combine leisure=pitch with building=*; riding arenas which are located in a building shall rather be mapped as separate objects. This was previously discussed on the tagging mailing list.

• https://github.com/openstreetmap/id-tagging-schema/blob/main/data/presets/leisure/pitch/equestrian.json
• https://wiki.openstreetmap.org/wiki/Tag:leisure=pitch#covered
• https://wiki.openstreetmap.org/wiki/Tag:building=riding_hall