[Test/HT] Changed the output name in square_5500x5500_staggered_scheme_adaptive_dt.prj

See merge request ogs/ogs!3331

Added a description of HeatTransportInStationaryFlow

See merge request ogs/ogs!3328

[MPL] Kozeny carman model

See merge request ogs/ogs!3264

[GeoLib] Substitute Vector3 and DenseMatrix by Eigen analogons Part 2

See merge request ogs/ogs!3320

 HeatTransportInStationaryFlow to zero.

[GeoLib] Substitute Vector3 and DenseMatrix by Eigen analogons Part 1

See merge request ogs/ogs!3319

[web/benchmark] Fixed a formula display in "BGRa creep model"

See merge request ogs/ogs!3329

[PL/RM] Remove postNonlinearSolver call.

See merge request ogs/ogs!3324

Since it is not guaranteed that at least two randomly generated points lie on
the surface of the sphere, the test often fails.

Using Eigen::Vector3d for dot- and cross-products
instead of own implementations.

This helps to omit const_casts when the point
coordinates needs to be modified.

In the former implementation the output was implemented using references.

[Docu] Fix doxygen warnings.

See merge request ogs/ogs!3322