Feature: Export elevation profiles

A new item has been added to the elevation profile toolbar, which includes various options for exporting elevation profiles.
Profile plots can now be exported as:

• 3D Features: exports the profile line as 3d cross sections, with z values taken from the elevation slices
• 2D Profile: exports the profile as a distance vs elevation chart (i.e. as shown in the elevation profile widget)
• Distance/Elevation Table: exports sample distance vs elevation values as a table

The results can be saved as DXF files, CSV files, or any of the standard writable vector spatial formats shapefile geopackages.

This feature was funded by Point cloud processing and 3D data enhancements crowdfunding

This feature was developed by Nyall Dawson