A pointer has the same semantics as an optional in this case.

The function wraps the original createConstitutiveRelation()
function while checking the "id" attribute in the
<constitutive_relation id="0"> tag. The return value becomes
a map from int to constitutive relation pointers.

Better Jenkins log parsing

See implementation in Jenkins library:
https://github.com/ufz/jenkins-pipeline-library/commit/c290e5beebb1333643be40a4a83a8184c173b6e4

MaterialIDs for solid models preparation

Update documentation mismatches in other getConfigAttribute*().

[web/BGRa] Recovered the display of the formula of the elastic tensor and a table

Add OGS_FATAL for not implemented/recognized element types.

CMake args tracking in exe and installations

Stores user-given CMake variables from the recent CMake run into cmake-args file. Install cmake-args file and CMakeCache.txt.

HC process revision

Note: The differences for the comparison of the comparison between ogs5 and ogs6 arose from an abs(..) which I added compared to Marc's approach. If I do the same for the calculation, there is no difference.

?

-elder benchmark updated

-heterogenous HC benchmark reference files updated

-goswami benchmark temporarly removed from HC-tests

-SimplySynthetics: ConcentrationAndDiffusionOnly needed small changes in .prj file

-SimpleSynthetics: Project file adapted

-SimpleSynthetics :DiffusionAndStorageAndAdvection modified. Variable density model (p and c dependant) added, non boussinesq effects observed, consistency check,
		update of reference files

-SimpleSynthetics: DiffusionAndStorageAndGravityAndDispersionHalf- A new project has been set up, since the old setup was not converging anymore due to too large
		differences in density leading to problems in non boussinesq treatment.

-SimpleSynthetics: DiffusionAndStorageAndAdvectionAndDispersion- reference files updated. _max iter value in project file sligthly increased.

-SimpleSynthetics: DiffusionAndStorageAndAdvectionAndDecay- reference files updated. density model in prj file changed in order to account for storage.

-SimpleSynthetics: DiffusionAndStorageAndAdvectionAndDispersionHalf- reference files updated. density model in prj file changed in order to account for storage.

[HC] first annotations included

[HC] reduction to one shape matrix N

[HC] clang-format reformatting of branch