Implement TIN Rendering type

[MattReimer]

In discussions about upgrading to the new warehouse this week with @kunztr we noticed that tin types are not loadable in QRave.

1. Can QGIS render tins in any kind of way?
2. Can we implement a TIN renderer for QRave to support project types like topo

[joewheaton]

@MattReimer assuming you've seen this: https://gis.stackexchange.com/questions/349069/opening-tins-in-qgis

This tutorial suggests using some GRASS functionality to create TINs and I'm not sure what format they are stored as, but they're almost certainly different then the ESRI TIN format.

[joewheaton]

See also: lutraconsulting/MDAL#164