Add support for offline geocoding

@mraross commented on [Wed Dec 20 2017](https://github.com/bcgov/api-specs/issues/269)

An offline geocoder doesn't need to be hooked up to the web to work. It could take the form of a containerized API or a standalone desktop Java app.

Requested by Elections BC for use onsite at polling stations during elections

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@ll911 commented on [Wed Jan 03 2018](https://github.com/bcgov/api-specs/issues/269#issuecomment-355165300)

docker package and allow to run locally or anywhere

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@cmhodgson commented on [Wed Jan 03 2018](https://github.com/bcgov/api-specs/issues/269#issuecomment-355171193)

Not sure that a docker package would be an acceptable solution for the clients in mind (on-site elections registration was one?) due to complexities of install and system requirements - however, if the geocoder is to run in its present form this is probably the most straightforward way to package up all of the components.

An alternative approach would be a java desktop app of some kind, a simpler install, potentially reduced requirements, but does require much more work to create it.