[Divisions] Add support for Geographical Regions

[DavidKarlas]

Description

There are many regions in the world that people often search and some apps might want to highlight on map when searched for. Hence proposing adding new subtype called "geographical_region", with "classes", "disputed"(https://github.com/OvertureMaps/rfd/discussions/52) and "region" for start.

Reference

https://github.com/OvertureMaps/tf-admin/issues/100
https://github.com/OvertureMaps/rfd/discussions/52
https://github.com/OvertureMaps/tf-admin/issues/102

Testing

Added example cases.

Checklist

Checklist of tasks commonly-associated with schema pull requests. Please review the relevant checklists and ensure you do all the tasks that are required for the change you made.

1. Add relevant examples.
2. Add relevant counterexamples.
3. Update any counterexamples that became obsolete. For example, if a counterexample uses property A but is not intended to test property A's validity, and you made a schema change that invalidates property A in that counterexample, fix the counterexample to align it with your schema change.
4. Update in-schema documentation using plain English written in complete sentences, if an update is required.
5. Update Docusaurus documentation, if an update is required.
6. Review change with Overture technical writer to ensure any advanced documentation needs will be taken care of, unless the change is trivial and would not affect the documentation.

Documentation website

Docs preview for this PR.

[vcschapp]

1. Should we be adding the linked RFD into (RFD 52) into the schema meeting so schema TF can be involved?
2. This PR seems to go beyond RFD 52 in some respects. Why, and what are the use cases? Especially, what is the use case for subtype=geographical_region,class=region versions just subtype=disputed as @stepps00 suggested in the RFD?