add native total curvature algorithm from the terrain analysis library (Request in QGIS)

[qgis-bot]

Request for documentation

From pull request qgis/QGIS#64307
Author: @alexbruy
QGIS version: 4.0

add native total curvature algorithm from the terrain analysis library

PR Description:

Description

Adds the Total curvature algorithm to Processing.

The total curvature filter has existed in the terrain analysis library for years, but it was never exposed in the GUI. This PR adds it to Processing alongside the terrain analysis filters that are already present.

Commits tagged with [need-docs] or [FEATURE]