Support for Range data type

PostgreSQL has supported range types since 9.2 (https://www.postgresql.org/docs/9.2/static/rangetypes.html).

And interestingly, we have a customer who'd like to store KPI targets as a range, and store it as open data in CKAN as they want to link to the raw data from their dashboard.

Perhaps this can be supported post-load by adding range type support using the Data Dictionary datatype casting feature?

Start by reviewing PostgreSQL range types and CKAN's Data Dictionary datatype casting feature. Determine the intended post-load integration and define the supported range behavior and acceptance criteria before identifying implementation and test locations.

Written by the indexing model from the issue text.