Add field for operator:wikidata

[kjonosm]

See #168

[tyrasd]

This PR only defines the field, but does not add it to any preset. Without adding it to any preset, the field would be essentially useless.

Did you intend to add this field to any preset which includes the operator field? That would have the major downside of being a lot of effort to change, as it involves changing hundreds of presets. I think we should think about a better solution, e.g. involving an improved "wikidata" field which can directly work on a tag-triplet, e.g. here operator + operator:wikidata + operator:wikipedia. That would require some changes to the schema, however.

[kjonosm]

Did you intend to add this field to any preset which includes the operator field?

@tyrasd: That was the idea following the already featured subject:wikidata field. However, not to all presets with operator=* info but only those where operator:wikidata=* is commonly used, see NSI for reference. If you don't consider merging this pull request (and others adding *:wikidata fields) please let me know and I am happy to delete them.

[matkoniecz]

Without adding it to any preset, the field would be essentially useless.

What about objects where this tag was already added?

[kjonosm]

What about objects where this tag was already added?

The field still needs to be added to the respective presets...

[matkoniecz]

@kjonosm Do you plan to fix technical issue that was mentioned in comment above?

[kjonosm]

@matkoniecz

Do you plan to fix technical issue that was mentioned in comment above?

That depends on the decision of @tyrasd regarding the above mentioned "better solution".

Improving the wikidata field within the schema builder is unfortunately beyond my skills.

But if people are okay to adding the field to existing specific presets I am happy to update some presets where I consider it useful.

[matkoniecz]

But if people are okay to adding the field to existing specific presets I am happy to update some presets where I consider it useful.

given that changes to schema are stalled and beyond your abilities anyway (and also mine, at least right now - maybe I could spend time to learn what ideditor/schema-builder repo is doing)...

I guess I would try probing PR adding it to just some presets (maybe low number like 10 or 30?) to see whether it will get accepted? At least I would do this if I would be making such PR.