t_curr is not used afterwards.

The function is identical to the const version and
not modifying.

Removing the return value.

[Tool] Remove points from geometry not used in polylines or surfaces

See merge request ogs/ogs!4702

This is almost a copy of MeshToolsLib::generateRegularNodes().

md Test markUsedPoints() polyline

CI fixes

See merge request ogs/ogs!4720

[web] Added link to ogstools on the docs overview page.

See merge request ogs/ogs!4718

[web] Creating Tutorials section and moving Video Tutorial there

See merge request ogs/ogs!4716