Fixes out-of-memory errors in e.g. ProcessLib.

Uniqueness of titles are required in the same menu section (benchmarks)

This was removed in https://github.com/ufz/ogs/commit/8462108.

Nonuniform Dirichlet boundary conditions

SmallDeformation gravity.

Store the results in the process data.

Documentation and restructuring of component transport tests

Restructure PhaseField

The default dtor is already present in the base class.

Remove unneeded includes, reorder few lines for the sake of identical
code structure with SDFEM.