Add Geography Author API spec

[janedotx]

This API extends the proposed Geography API to include the ability to add/edit/remove Geography objects via an API, for standardized creation of GUIs other other integrations with geographic data sources

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[schnuerle]

Note that for 1.1.0 we have merged the new Geography API to the 'dev' branch. Please update this pull request with the latest code, resolve any conflicts, and make references to the Geography API where appropriate, e.g. with UUIDs.

[schnuerle]

See the notes from the last WG call.

• Just like Policy. Useful to see and have them in draft
• Maybe both this and Policy in some new Authoring repo on top of MDS
• Both help cities make changes and drafts to APIs they serve: Policy, Geography