Feature: IVEA projection

[felixpalmer]

Overview

This PR is stacked on top of the root PR: OSGeo#4758 - please see there before reviewing

Projecting with DSEA onto a icosahedral net yields a better result (less cusps) that using ISEA. This approach has been referred to as IVEA in some places, for example https://dggal.org/

The purpose of this PR is to show how an alias can be added for an existing projection to make it easier for end users - some of whom may find it confusing that a dodecahedral projection can be unfolded onto an icosahedral net.

Change list

• Register new projection
• Include in test render scripts

Example renders IVEA

Note cusps compared to IVEA

[felixpalmer]

Leaving open for reference, but will require reworking to be compatible with new approach that uses conway meta to cut up the polyhedron and a definition for the parents net