add geolocation information to Hosts responses

[roperzh]

Related to https://github.com/fleetdm/confidential/issues/1610, this adds information to our docs about hosts responses containing geolocation information.

Checklist for submitter

If some of the following don't apply, delete the relevant line.

• [x] Documented any API changes (docs/Using-Fleet/REST-API.md or docs/Contributing/API-for-contributors.md)

[mikermcneil]

Thanks Roberto!

(FYI I removed the request for Des to review for now to save time, since he will review post facto after this is merged)

[roperzh]

hey @ksatter , just pinging you to make sure this didn't slip through the cracks since you were at the conference.