DATAMONGO-858 - Add support for common geospatial structures.

Backed the geo spatial structures of SD MongoDB by the new geo spatial structures in SD commons. Deprecated the MongoDB geo spatial types to make users aware that we're going to remove them in one of the following development iterations. Added custom conversions for basic geo spatial types.

This PR depends on some work in SD Commons: https://github.com/spring-projects/spring-data-commons/pull/68